A miner goes into town after several months of very hard work. When he gets to town, he decides to go to the local whorehouse unload some pent up frustrations.
He picks out a whore, takes her to her room, and she gives him a skillful blow-job.
When she's done, she reaches under the bed, pulls out a big mason jar and spits his wad into it.
"What the hell is THAT for?" he asks.
"Well", she says..."Me and my girlfriend have a running contest. Whoever has more at the end of the week...gets to drink both jars."