Hey why does my new gfs best friend dislike me and sorta interrogate me and tell me she'd castrate me if I did anything with her friend?

I mean I just came down her throat and the girl I'm seeing is a virgin and all so I guess it's a new thing for the best friend

But why? Why such hostility?

Im not hurt or bothered or anything I'm just curious, I was holding frame and I told her that I'm probs going to smash and dash her friend (gf knows I'm joking), she asked me a bunch more questions to try and corner me