My [M] girlfriend [F] drunkenly told me she wanted me to fuck her ass

So my girlfriend and I set up a little pool for July 4th weekend and were having a great time in the sun. The afternoon went on and the weather got a little cooler so we moved the party inside.

We had been drinking and I had been admiring her tits in her new bikini. It didn’t take long for us to start fooling around and move to the bedroom.

Now, my girlfriend can be a freak but she isn’t usually into anal for a combination of reasons, but this evening was different apparently. We had already broken out the wrist and ankle cuffs, I love cuffing a girl up. We were on the bed, her ankles tied together, but her hands were free.

I have had a fantasy for a long time where I fuck her ass, watch her get her ass fucked, DP her, you name it. So I was fucking her pussy doggystyle when I got the idea to lick my thumb and rub it against her asshole. She felt my thumb and immediately told me to stick it in her ass.