try a cock ring, I know it sounds wierd and wrong, seriously it's nothing big. Can be made of many things, you could even use a rubber band as long as it was thick and not too restrictive. (should be snug, not painful) It tightens at the base to keep the blood from flowing back out so you stay hard longer. (It isn't bad for you unless you keep it on for hour or more) Otherwise, try not to let your thoughts wander while your getting your condom on, keep thinking sexy things, and for god's sake tell the lazy slut to help you out....no one likes a dead lay.