BB, they should shrink up a little bit as you wash them a few times. Try to avoid stretching them as they dry.

If these are the 80 percent wool socks, they stay up on my legs about 50 percent of the time. :-) I think mine are improving as I use them, they seemed a tiny bit large when new.

If you don't have some flashes that you can easily slip off of their garters, you can make a pair with elastic and velcro.