As for positions, the only way that I have been able to do it comfortably in the start is doggie and then, if so choose can change to another poistion.

However, ever since my daughter was born, I have really been unable to do anal without a large amount of discomfort and pain. Maybe is is because she rearranged the furniture while she was in there and didn't put it back when she moved out, I don't really know.