. . . . . . . . . . . . . . start by asking him if he thinks your boobs are big enough, hope this will "spur" a conversation regarding "size" of things ? Then you can in a jokin manner, ask him what size/length his penis is ? Start a conversation by saying that one of your girlfriends boyfriend, husband has a real big penis. This may spur a conversation and he may feel guilty asking you if you are happy with the size of his penis and you can say in a nice way, "well, no," "you can use more size", then tell him you did a little research on the internet and found multiple "Penis Enlargement (Penis Enlargement)" sites and give him this site (MattersofSize.com). He may be selfconscious and do Penis Enlargement exercises in secret and hope you will notice a difference in size, but you also know that it doesnt happen over night !
Good luck