Transmen (female to male) use not duct tape for whats called binding ie taping booba down to be as flat as possible

Transfems (male to female) use not duct tape for tucking, which is a bit more involved than what you said but yeah its exactly what you think it is, genitalia taped down again to be as flat as possible

Kinesiology tape is a good tape to use for both of these purposes