Rubbing on her ass and cumming on her back. Stepping it up

Do you rub your cock in your wifes ass crack and cum on her ass and back? It's better than jerking off alone.
My wife would often tell me to rub it in the crack of her ass and shoot onto her back. That was ok, but I needed to step it up, so I first tried it with a buttplug. The feeling of prostate stimulation felt good as I rubbed and stroked on her ass. There was still something missing, so the next time I knew she was going to let me do it, I put a dildo in ass. I wear a thong, so the thong held the base of the dildo and kept it from falling out. Every time I moved back and forth, the dildo came out about an inch or so, then went back in. This felt out of this world and I had one of the biggest and most intense orgasm ever. The trail of cum led from her ass, up her back and pooled in the small of her back. When I told her that there was more cum on her back than ever , she turned and looked at me and told me I knew what to do . That meant "cleanup time". I licked my way from the top down to her ass. She had no idea that I had a dildo in my ass until I told her.