Semenarium
From HellWiki
Semenarium is located in Weezer Village, and the hours of operation are 8:00am to 10:00pm. It is on Riverfront Street.
Those with the ability to produce semen (i.e. you need a dick) can donate their 'genetic material' to the Weezerian collective. Either wank into the collection machine downstairs or do your business in a vial and sell it to Jack. You'll be paid a hefty sum, but this can not be done more than once. The amount of money you receive seems to depend on factors such as the number of your mutations and the amount of xp you have. In other words, it may be worth waiting a while before donating.
Jack also offers a job for the more adventurous.
Goods for sale:
a semen vial $ 1