It depends on how close you are. If you're just Facebook friends and don't really meet in person anymore, I'd say go for it. It's not like he's going to share that with anyone else.
You could approach him in a cute way, like confessing you had a crush on him in high school (even if you didn't), then bring up the ad. Make sure to act all embarrassed when you bring it up. He'll be flattered even if he turns you down.
I had masturbation candy in high school, but the purest memories of lust come from junior high, when I started puberty. But neither they nor I can go back to being that young.