when my penis is hard its average about 6 inches give or take but quite commonly when its not or especially about 15-20 mins after ive come it grows to quite a small size to the extent of about an inch and looks like what it used to be like when i was quite younger... while nightly rituals dont bother me since it returns to a normal size the size while not hard does shrink compared to the average guy my age... what causes this? i believe it has only occured in the recent years and while the majority of times its not all the time