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Flaccid - covered, erect rolls back on its own. One of the worst experiences is long journey erections when it rolls back, and then when it rolls forward on going soft takes a bite of pubic hair.
I think that, with most intact guys, the answer to this question is determined by the length and tightness of the foreskin -- and these things very a great deal among men and boys.
Mine is medium long and fairly loose. It stays covering the head naturally when I am soft. If I pull it back when soft, it rolls forward again. If I get hard without stroking, the skin naturally pulls back about 2/3 of the way leaving most of the head exposed. If I or my partner pulls the foreskin back when my cock is hard, it will stay parked behind the corona of the head until it is slid forward.
It all feels wonderful by the way. Examples of all the states of my foreskin are in my gallery, if anyone wants visual aids.