Question: how to make a guy who has a girlfriend jealous?
Answer: Go out with your friends. Guys feel very insecure when girls go out without them. ... 
Ignore his texts and calls. ... 
'Accidentally' touch another man. ... 
Be mysterious. ... 
Show him that you don't need him. ... 
Tell him that you have to work late. ... 
Compliment his best male friend. ... 
Talk about your ex.