I can't seem to maintain my weight. If I eat what I want when I want, I gain weight, but if I eat any less I lose... Any help?

How long have you been maintaining? How much are you fluctuating? Do you track calories?

Sounds like you may be changing you intake too drastically. When maintainers trainsition it's usually 50-100 cals/day at a time. Also a little intitial gain after an extended period of time at a deficit can be expected. What kind of gain are we talking about. Weight fluctuates during maintenance as well.