pear bum

Pear bum - a person with a pear shaped ass, usually sagging and obese. More like a rotting pear than a firm, fresh, delicious pear.

When I saw him walking down the street, it was obvious from his pear bum that he was over the hill in terms of virility. Had he paid attention to the Chinese herbalist, he could have an Anjou Pear Bum, but instead he has a Bartlett Pear bum, and the sadness is infinite.