Yup, riding bicycles and motorcycles. Usually they don't have enough time to inject much venom in hit-and-fly encounters. Unless they can latch onto your clothing or arm/leg hair, etc.

But if you're highly allergic or sensitized, even a small amount can be painful. Fortunately I'm not allergic and barely react unless the critter injects a full payload. I tend to react more to the formic acid from red ant bites (painful lumps about the size of a nickel or quarter) than to bee or wasp stings. I got stung two or three times quickly while stopped on the local MUP trail head the other day, all on the right forearm. I'd stopped to chat with a couple other cyclists. Turned out the sign I was leaning on had a yellow jacket nest between the double-faced sign. Other than the mild and brief discomfort of needle-prick stinging pain, I had no reaction. Probably didn't inject much venom. I never felt the critters so they didn't land, just hit and run.

If you don't already take a daily second generation antihistamine you might consider it. Zyrtec and generics work for me for respiratory allergies and to minimize asthma problems. Don't routinely take first generation antihistamines Benadryl if you can avoid them (besides making folks drowsy the anti-cholinergic effect can cause confusion and other complications for some folks, particularly when there are interactions with other meds). But I do usually carry a first aid kit that includes diphenhydramine (generic Benadryl). It's a good emergency relief med for folks who are highly allergic, if they don't have an EpiPen or other suitable emergency relief option.

A topical ointment containing diphenhydramine and other medications can help too -- supplemental or alternative ingredients in ointments can include hydrocortisone, salicylates used in muscle pain relief creams and for some skin rashes and even dandruff, eucalyptus and others.

I've used these on family members who had severe allergic reactions to wasp stings, but had no prescription emergency relief meds like the EpiPen or old style epinephrine injection kits (which are useless in real emergencies to the user, and useful only in the hands of skilled and experienced practitioners -- it can take up to two minutes to fill and administer those old style epinephrine injection kits, far too long for self-administration by sensitive victims, and often too long for panicky family or friends who are trying to help). In the case of a cousin who was dangerously allergic to wasp stings, the ER personnel confirmed the use of a single diphenhydramine capsule and topical ointment helped minimize the reaction to a sting on his neck that began swelling rapidly.