Go to a home health care store and look for something called a bed wedge. Lay on your back and use the wedge to raise your pelvis and have your guy enter at a horizontal angle. This may or may not work, so you might want to try the angle game with a pillow before investing in the bed wedge.
Also, you might try putting something between your pelvises...a roll of toilet paper or a pair of socks rolled up has worked for me in the past. That external pressure, coupled with the angle variation inside might do the trick. My ex thought it was all about the clit until we tried this.