We just finished a week playing the card game Spoons, and I created a list of things the winning student (the first to get four of the same part of speech) could choose to tell the losing student (the only one without a spoon) to do. I don't want to actively encourage the slapping on the wrists or backs, but I also don't really stop it when I see it either, that's how a lot of Korean kids have fun! I did take out a student's suggestion of "couple dance"--boy, did I get some sexy dancing from my students with that one.
Nevertheless, I think it's important to think about what was happening. My kids were constantly pressing each other to play the game--to match parts of speech--in order to watch one of their friends dance/sing/etc (or even risk their own embarassment!). I played with them, too. When I lost, I had to tell a student I loved her, and in another instance had to dance around the room like a ballerina. I had two students ask me to marry them, which was sweet. :) Not only are they encouraging each other to practice grammar, they're self evaluating, as the loser always checks that all four parts of speech are the same just in case he can get out of embarrassing himself! It's a fantastic exercise for them.
On top of it all, it makes students way, way more comfortable with each other. As much as people have made the valid point that some students might dread situations where they'll have to embarrass themselves in class, it's important to acknowledge that we teach language and that in language learning, students HAVE to be willing to embarrass themselves. If we establish an atmosphere that it's okay, and even fun, to embarrass yourself, in dancing or in making mistakes, it only adds to the classroom experience. (Especially in Korea!!!)
I do love the spelling names with their butts--my favorite coteacher taught it to me. (but they should NOT be leaning over to do that!) That said, I think it's inappropriate for anything under high school or mature classes in middle school.
Here's the list I gave my students.
Make a funny face
Dance like a ballerina
Propose to someone
Tell someone you really love them
Ask someone for their phone number
Dance like a chicken
Dance like a monkey
Blow a kiss to someone! (공중으로 친구에게 뽀뽀날리기)
Bark like a dog
Dance like a robot
Snort like a pig
They've been awesome.