This is my new favourite sex position:
Took me a bit to google it and apparently it's called the nun.
The best thing is, that this way she can easily play with your ass while you **** her.
Since your dick is bent downwards a bit, it all feels pretty intense and you have a very enjoyable view of her butt.
Apparently it also feels quite good for the woman and it's not particularly exhausting, although it does require a bit of leg muscles.
Very recommended.