Our previous two appointments were very successful in obtaining useful samples for the study you've agreed to be part of, and now you're here for your final donation. This time is a little more intense than the previous ones, though. You've been instructed to edge yourself for 7 days prior to your appointment, but you were not allowed to ejaculate. Just think how good it will feel to finally release all that pent up tension as you give me your biggest donation yet with this final sample...