I dunno bout the tennis ball and such. If you can just get a sparring partner to through punches at you and practice practice practice would probably be best.
FYI, I used to box and one of the first things I found moving into MT was that bobbing like a boxer would is a sure way to get yourself kicked/kneed in the head
As E Kaye said you don't actually move your Head, but tilt at the Hips.
1. Drill it solo with a Maize bag. An homemade one will do. Do a 5 minute Round every Day for a few Weeks.
2. Dry Run it with your Partner's Jab. Have him slowly throw a Jab at you. Then a right Cross. Then random Jab or Cross.
3. Add in stepping. The Point of Peek-a-boo is to get in closer so add the Stepping in with the Dry Runs.
4. Have Partner increase the Intensity and Speed. Start with just the Jab. Do a few Rounds every Day. Do it w/ just the Cross. Finally with Jabs and Crosses mixed in.
5. After Days/Weeks...however long it takes. Have him add in other Punches, so you can discern between when to Peek-a-boo and when not to.
6. Depending on whether you are just Boxing, Kickboxing, or doing MMA add in the other Tools.
When you encounter fundamental Problems, go back a Drill or two and correct it.
Bobbing is like a small squatting movement with your legs while keeping the rest of your upper body straight. Moves your head below the path of incoming punches. It's a down-up motion.
Weaving is a slight lean sideways at the waist. Moves your head to the left or to the right of the path of incoming punches. It's a side-to-side motion.
"Bobbing and weaving" is combining both movements simultaneously.
VERY succint PFP. Well said. One of the better Descriptions I've read for a commonly asked Question.
Think of a Bobber in Fishing. What doe sit do when a Fish Bites it? That's why it's called a Bobber.
And when some Asshole is in Traffic and WEAVING in and out of Lanes, what is he doing?
In my Gym, I like to answer Questions with Questions and Visualizations. Being involved and invoking Images seems to effect postive Transfer of Understanding.
It's not too long and has some nice sequences showing the separate motions for bobbing and weaving. Also shows him drilling those while stepping forward and moving around.