girlfriend wants me to motorboat her vagina and make tremendous production while i am going downtown. i am into it but have a problem maintaining this posture for longer than a couple of dozen seconds. we have vibrators but she insists that i use my mouth to accomplish the deed. any advice on techniques for going down? is there anything else i could do that might please her besides the motorboat technique? thanks in advance. cliffs: girlfriend needs prolonged vigorous oral. not physically likely/possible. recommendations??