You shouldn't do that unless they are bad for each other.
If a boy has a girlfriend then he is considered taking and you should leave him alone and later he may break up with his girlfriend.
tell on him and tell him leave my girlfriend alone.
If the boy is fooling around with you then confront him and if you are sure that he has a girlfriend, leave him but make sure to show his true face to people you know. But if he is not fooling around with you then it might just be a misunderstanding. This could mean a shady person or an outgoing one.
Only if you want to be his girlfriend. it does if u say yes
you hog-tie her.
Hit her in the face.
If this boy has a girlfriend, you need to respect that he chose her. You can continue to be a good friend to him, but you can save the schemes to make him mad for you until he is single again.
you cant make sure - if your girlfriend feels that you are too suspicious, jealous or controlling, it might cause her to leave you in the first place.
make him like you better
If the boy has a girlfriend, find a guy that doesn't have a girlfriend.
If she is your EX girlfriend, the she is nothing to do with you any more, do as she asks LEAVE HER ALONE to make a new life without you.
If a boy already refers to you as his girlfriend when you are not, and even claims that you have made out when you have not, he is just being overprotective by passing a message to other boys to leave you alone for himself.