I have a 3-year-old (newly 3), and for naptimes, I always do "bumpalumpas." I carry her up the stairs (pretty much the only time she gets carried nowadays, so it's special) bumping her up and down as we go, saying "bump-a-lump-a-bump-a-lump-a." For whatever reason, she loves it. She loves it so much that all I have to do when it's naptime is tell her, moving my arms up a down a bit, "look, the bumpalumpas are starting!" She runs and jumps to get into my arms because, hey, if she doesn't hurry, the bumpalumpas might go on without her. It's really cute, and oh-so-convenient. We do all sorts of little playtime things to get her in bed, like I'll sing "rock a bye baby" acting the song out (blowing on her for "the wind blows" and when the "baby falls" I drop her into her bed so that she bounces a bit). Makes naptime so much more a game.
I have to admit, though, that I'm guilty of the "okay?" as in, "do you understand and agree to obey?" The correct response (from the child) is "okay." If I don't get a response, I'll say, "Okay?" again, until they agree. I've tried to work on saying "do you understand?" and I do that sometimes, but it's not quite as natural.