The crucial woman in the threesome for me is the one working the cock. Some women really are not good at stroking cock or teasing it. But if she is good at it, your cock can come close to orgasm many time and her hand gripping or slapping your balls can make your body start over. Then she can choose to leave you denied and humiliated or bring you to a great orgasm especially if she ends up using your cock to fuck her mouth with cum shot included.