Helpful prerequisite:  a WAIT or STAY cue.

Here’s how a dog performs the “finished” trick:

While you are standing with feet just slightly apart, your dog circles behind you, peeks her head through your legs and stays in that position for at least a few seconds.  (Don’t worry, if you happen to have a very tall dog, you can teach her to peek through your legs in a crouched position.)

Once this trick is taught, there are many amusing cues you can choose from.  Here are just a few examples:  go hide; say hello; who’s a tough dog? (especially funny for breeds with intimidating looks); where’s the mouse?; are you ready to perform?  Spend some time thinking about what cue to use.  That alone can really enhance the whole trick performance.

I’d like to offer you a couple options for teaching this skill. 

The first option is appropriate for any dog who is not so tall that she can’t peek her head safely through your legs (safe for you, that is).  It’s very easy to get this trick started if you position yourself in a doorway.  Bathroom doorways are usually more narrow than a main door.  (A corridor would work, too.)  Ask your dog to wait or stay behind you, and then stand in the doorway with your feet far apart.  (Basically, if the dog wanted to pass you, make sure the easiest route is through your legs.)  Once you are set up, calmly say your dog’s name or use a few encouraging words so that she wants to look at you.  Because your back is turned, most dogs will want to pass through the doorway to be able to look at your face.  As she starts to make this move, be sure to click (or use a verbal marker) the moment the dog’s head just peeks between your legs. 

For clicker savvy dogs, the click may instantly arrest any further forward motion, and if this happens, give the treat to the dog while she is in the correct position between your legs.  Do this for the first few repetitions.  In order to get the dog reset for the next repetition, just toss a second treat behind you. Make sure your click occurs just as the dog’s head begins to peek through your legs.  If you are late with the click, you are more likely to reinforce the behavior of passing through your legs rather than peeking between your legs.  Sometimes, even if your timing is good, the dog may still walk through your legs.  No big deal, just try toning down the initial verbal “enticement” you use, or don’t say anything at all and just wait for the dog to make the first tentative move between your legs.  Also, if most of the treats you give the dog are delivered BEHIND you, it won’t be long before the dog learns to cut off unnecessary forward movement through your legs – she’ll learn she can get to the treat faster if she just peeks through instead!

If you are using a clicker, please be careful where you are holding it so that it isn’t close to the dog’s ear.  If your arm is hanging by your side, I think the click sound will be too loud.  Hold the clicker behind your back instead.

The second option for eliciting the “peek” behavior is to use a target.  This is useful in several situations:

• Some dogs are a little nervous at first about maneuvering between your legs.  But if your dog is proficient at targeting, she will have something to focus on and you should be able to get her peeking through your legs quickly.  For the target, you could use your hand (if the dog is fairly tall), a dowel or a target stick.
• A target stick will also be useful with very tall dogs.  Position the end of the target stick near your ankles so the dog must bow low (or crouch) to touch it.  
• Targeting also came in handy with my fast-moving little Papillon.  By carefully positioning the end of the target stick, it was easy to teach her just what position I wanted her to be in.  Otherwise, she tended to dart through or around my legs too quickly.

Once you’ve had a number of little training sessions using the target, and your dog is positioning herself between your legs promptly and with confidence, start looking to fade the target out of the picture.  For example, when the dog is waiting behind you, present the target between your legs, but as the dog moves toward it, slip it out of the picture before contact is made.  Click and treat when the dog is in the correct position.  After doing that a number of times, get rid of the target entirely and wait for the dog to offer up the peeking behavior on her own. Give her a jackpot on her first success!

If you started your training in a doorway, now it’s time to gradually move out of this position.  Back up a step or two, and continue to click/treat successful peek behaviors.  Before long, you should be able to work in an open area without “barriers” needed on either side of you.

The better the dog gets at peeking through your legs, the more challenging you’ll want to make the exercise.  Here are some areas to work on:

• Once the dog is in the peeking position, begin to delay the click/treat so she learns to hold the position longer.
• After each successful (clicked) behavior, throw the treat a few feet behind you.  One reason I suggest this is because the dog is less likely to want to pass completely through your legs if the treats are always delivered behind you.  Also, by tossing the treat, you’re buying a few seconds of time to reposition yourself.  At first, remain fairly close to the dog while continuing to present your back to her.  When the dog finishes the last treat, she’ll see you standing nearby, and will likely offer the peek behavior again.  Be sure to add distance gradually, just one step at a time. If she happens to circle around to face you instead, just turn your back to her again.  The behavior of circling to face you will extinguish if it’s never rewarded. 
• When the dog performs reliably from a position directly behind you, start angling yourself slightly so your back is no longer fully presented to the dog.  This will require her to maneuver slightly behind you in order to get into the peek “launching” position.  Little by little, continue to adjust your position, until you are finally facing her.  Done gradually, the dog learns to circle around you as needed, so the peek behavior always occurs from back to front. 
• Gradually begin reducing the space between your legs.  The eventual goal is for you to stand in a “normal” position with feet separated just enough so the dog’s head can peek through.  The tighter the squeeze, the funnier it looks!

At some point, it’s natural for dogs to start experimenting to see if other behaviors will also pay off. Some of the more popular attempts are peeking from front to back (it’s cute watching their tails waving in anticipation of the expected click/treat), and/or dashing clear through your legs.  The obvious thing to do during these experiments is to ignore them!  They will go away if they are not reinforced.  (In the meantime if you have a Pit Bull type dog with a big block head like my dog has, wear knee pads with the cushions directed inward for protection!) When you see that the dog understands the correct behavior and is performing reliably from any starting position, you can add your cue.