In S4E01 "A Hole in One" Jim has to give up his vices: no drinking, no smoking, no more hot tubbing.

Of course he relents on his promise and when he has to get his sperm count tested, he comes up with a crazy plan to fool the lab.

The scene at the doctor's office when Cheryl finds out and the following scene at home with Jim, Andy, Cheryl and Dana, and the funny lines thrown at each other is typical for this sometimes "slapstick" show: over the top ridiculous and hilarious.