Cry it out theory

Ugh. Andy is getting so much more mobile in his crib that it's getting harder to settle him down at night and for naps. He will sit or stand up in his crib and he's so tired he can't figure out yet how to sit down so he just cries. So I go in and settle him back down and that, naturally, stirs him up a bit, too. I imagine he'll figure it out before too long, but this interim step is hard because I really don't like listening to him cry.