What is so funny about this?!? My girlfriend went on a giggling fit about it I don't understand?

Okay here is what she was laughing at some guy on TV got peed on. The many peeing on him said "lemme buy ya a drink". My girlfriend looked at me and said he shood have taken a dump on him and said "buy a steak" or something and she started giggling for like 30 minutes. I don't understand how this is funny.... let alone cause her to laugh like this.