Almost everyone has a bucket list of sexy spots where they want to have sex. But if you’re doing it in public, odds are you won’t be alone. (And we’re not talking about a creepy bystander watching for kicks.)

Faecal bacteria, norovirus, and MRSA are just a few of the nasties that can linger on hard surfaces in high-traffic areas, and all that skin exposure puts you at an extra risk of infection. We spoke with University of Arizona microbiologist Charles Gerba, Ph.D, about five spots you may want to cross off your list.

Aeroplane Toilets

These tiny, cramped quarters are the absolute worst offenders, says Gerba. “Seventy-five or more people use a single restroom on a plane before it gets cleaned and not many are washing their hands effectively.”

So it’s no surprise Gerba’s research found E.coli all over airplane bathrooms. Knowing that, the mile-high club may not be one you want to join.

Gym Locker Room

MRSA, staph, strep, norovirus, ringworm—you name it, and it’s been found inside the gym locker room, a perfectly warm and moist environment for bacteria to thrive in. (We wouldn’t walk barefoot across most locker room floors, let alone expose other, uh, body parts to gym bugs.)

Movie Theatres

If the sticky floors aren’t warning enough, Gerba says movie theatre seats and handrails aren’t washed regularly, and one swab test even detected staph on theatre seats. Avoid getting handsy (or mouthy) when the lights go down

Playgrounds And Parks

Have you ever seen playground equipment being cleaned? Neither have we.

Cold and flu germs, plus human and animal faeces, are all over parks, says Gerba. Next time you want to get down on a swing, remember 20 kids probably wiped their noses with it earlier.

The Beach

Thanks to garbage, sewage, bird poop, and other fun-in-the-sun factors, beach sand makes a pretty nasty surface for sex. (One study found that it’s dirtier than the nearby water, and could lead to issues like diarrhea, infections, or rashes.)

And don’t forget about the threat of beach ticks—they can actually attach to your nether regions and transmit diseases like Lyme disease.