I want to have sex with my best friend's girlfriend

Get ur own gf fucking cunt.Cher'

21..26 is normal
16..23 is not. cuz she has a life to build at the moment and youre playing the role of a scourge.

None of this is normal!

Kill yourself.

Completely normal and depending on where you live it may not even be illegal.

Might b normal or common but also it's more trouble than its worth. From what I've seen even a consentual OK even with your friend's "blessing" or "participation" easily turns around ... often to guilt, anger & worse. Its kind of looking for trouble ... why risk the friendship & more when there are plenty of other opportunities?

16 ?

Think of her feelings and yours 20 years from now. Don't corrupt her at this age.

It might be normal, but if she's 16 you should stay away from her. At 16 she's just a kid bro

I heard a story where a kid like you almost got shot for doing exactly what you two are doing. Who was the shooter? It was the girl's father. He learnt his lesson, you two need to.