Good, because there's nothing to brag about. Sex is so commonplace that any guy who feels the need to brag about having sex probably feels insecure about themselves. These type of men seek the praise of other men, and feel a sense of accomplishment when a male buddy pats them on top of the head and says "You did well".
Isabel, see post 24 :-)
Plus, women like a guy who doesn't "kiss and tell".