Men don't "have to," but it is weird if he does not because EVERYONE, men & women, have nipples.
No, you must not forget that only Hawaiian men with out penises can have have large breast but no nipples
Yes we all have different nipples. Some people have traffic cone nipples, quarter nipples, dime nipples, and many many more :)
Most gay men enjoying having their nipples pinched, sucked, bite on while having sex. Overtime their nipples will become more erect and grow in size. A: What rubbish! Gay men's nipples are just the same as any man's.
Both men and women.
Pump them up
Yes hairy nipples are normal for Men... but for girls they usually dont grow hair around the nipples.
Nothing it's just how where made.it would be weird of we didn't have nipples