FSET-420 Secretly fuck her best friend so she doesn't find out! 7

I want to do something lascivious with my girlfriend's best friend even if it's just once, and when I'm fantasizing about it, my girlfriend's best friend glances at me. No way, she likes me too! ? When I was thinking about such a thing, her best friend confessed to me, "I've liked you for a long time...". That word caught fire, so I secretly fucked with her best friend so as not to get caught!