I can't get out when my girlfriend wraps her legs around my head, is this normal?

Me and my girlfriend started dating a couple 4ish months ago and last month she wrapped her legs around my head and i was completely trapped until she let go. She did it again later that week and she's been doing it more and more I don't know why.
Any advice on how to get out to piss her off? Everytime she tries it im stuck no matter what, is this normal? How come she just no started doing this after 3 months?

Any tips will help!

I can't get out when my girlfriend wraps her legs around my head, is this normal?
Post Opinion