What are some sexual positions for obese couples?

My wife and I are expecting, and we are not finding out the sex. However, if we have a boy, she is adamant that we not circumcise him, and I am adamant that we do. I have researched article after article about the hard medical facts of circumcision and how it lowers the transmission rates of STD's such as HIV. It also helps with penile carcinoma, UTI's, and ulcerative STD's.
My intelligent wife believes that we should offer our son a choice of whether he wants it or not, and is afraid our son will feel the pain if he has it.