Snot Rocketeer here. But I only do it when there is no one around...no other cyclists, no cars, and not in front of houses where someone inside might see me, etc.. It's very gross, but it's effective...and my nose runs like a faucet. I am much better SR-ing with my left nostril, which is a good thing because that one runs about 75% more than the right one.

I also use my glove. If you wipe your nose on your glove, then wipe your glove really good on the side of your thigh, the glove is dry-ish and ready to wipe with again in no time. And I like to think no one notices the smudge on my leg from glove wiping.