A and I have been doing "this little piggy" with B a lot lately, and he's gotten to liking it so much that he does it to himself. He makes up his own words, and then when he gets to his baby toe, he'll tickle himself and laugh like crazy. It always has to be done on both feet, too, and if K's around, I have to do it to her (God forbid B actually touch her himself!).
B also likes making a buzzing noise like a B and swirly his hand around (finger pointed out), and tickles himself at the end. I love how silly he is and how much he enjoys laughing and having a good time.