Both of them are switches, at least, with each other.
Japan just has a tendency to be the sub more often because he doesn't know how to fight for dominance. America doesn't mind being a sub and sometimes even needs it, too, though.
Hetalia - NSFW Headcanons
By Wankker
A book of NSFW headcanons for the characters. Requests or suggestions are accepted ;;);););) UPDATE: THE IMA... More