There are many answers to that question (most of them - for women, anyway - related to corrective underwear and the use of moisturiser), but here's another.
You're with friends at a gig, and the lead singer kneels on stage for a moment, stands up again and notices he has chewing gum stuck to his trousers. He curses prodigiously, asking 'Who threw the fxcking gum on the stage?'
It is at this point that middle age hits. What do you shout back? Something cool, witty, or hip? Or:
"You want to put those trousers in the freezer mate - that'll get the gum out for you!"
Please note: this happened to someone else. No, really. Me? At a gig? With a haaaaandbaaag?