Butcher lived in an apartment over his shop

This butcher lived in an apartment over his shop. One night he was awakened by
strange noises coming from below, so he tiptoed downstairs and saw his
19-year-old daughter sitting on the chopping block and masturbating with a
liverwurst. The butcher sighed and tiptoed back to bed.
The next morning, when a customer walked in and asked for some liverwurst, the
butcher said that he didn't have any left. The customer was really annoyed; she
pointed to the corner of the shop and asked, "No liverwurst? Well, what's that
hanging on the hook right over there?"
The butcher frowned at her. "That", he replied, "is my son-in-law."