Nope, ya just take a whizz in their direction

Just in case my posting suggesting these things totally shattered your faith in humanity, I should say I've never actually done either, seen others do it, or even hear about it as a technique. I just threw that in to mess around a bit.

I'm not against informal pacelines, but I think riding someone's rear wheel is bad form unless you have reason to believe it's OK because it's dangerous and forces them to modify their riding style. Commuting is not the best time to draft because the distances are shorter, you have to vary speed more than when you're on open road for miles and miles, and many riders are weighed down by stuff they don't normally haul.