I make my sons kiss each other on the lips after they fight.
Why would you make them do that? I find it hard to believe they are comfortable with it.
I want them to learn to love each other as brothers should. If they are going to fight, they need to learn to make up.
Siblings making up is not the same thing as a romantic couple making up. It's not right for siblings to kiss each other, and it's really not right for you to force your own sons to do it. You need to stop doing this.
What do you mean it's wrong? I kiss my own sister on the lips all the time.
Well you kissing your sister on the lips is also something you should stop doing it. I am not sure where you picked up this idea that siblings should kiss on the lips, but most people would be appalled if they found out. When making up with a sibling, a simple hug is a good way to go.