Well, If you were using my Step-Father as a reference... You nailed it exactly. He literally has no ass. And now that he's gotten up in years, he has begun doing something completely disturbing.
I suffered for a number of years as a child being his apprentice around the house. Having to succumb to seeing his "plumber's crack" on numerous occassions. He seems to have solved this problem by hiking up is underwear up passed his waist and tucking his t-shirts into them.
I tried pleading with my moms to let him know that this fashion statement is not working, but given the alternative I guess the "Fruit-Of-The-Loom" barrier is an improvement. My Step-dad seems to think he has kept the same waist-line over the years, but actually that waist line has slowly been sinking. I am honestly contemplating getting him a pair of suspenders.
So if you texture it correctly, I would say that you have definately modeled the dimensions of a lot of aging Baby-Boomer Americans! Don't forget to expose the underwear, with the shirt tucked in.