Stop at a drugstore.
This should go without saying, but, if you’re having penetrative sex, especially with a new partner, you should be using barrier methods. If you’re not traveling with your preferred latex of choice, a quick trip to the local drugstore will save any potential coitus interruptus later, when you’ve found just the right spot (on their body and in the hostel) and it turns out you can’t go any further.
See if they’ll switch you to a private room.
If you have the money and your hostel doesn’t mind a potential overnight guest, you can be completely above-board and adult about the whole thing and just ask to move your things to a private room. Your new fun buddy can share the cost for one night, and if you don’t meet up again, you can move back to the dorms. If you do decide to repeat the process, you can negotiate staying in a place where private rooms are pretty cheap and move in together for a little while.
Be open to experimentation.
Due to the nature of some dorm rooms and gender-segregated bathrooms, it might be easier to find private spaces to get it on if you prefer or are interested in experimenting with people who are the same identified gender as you. Have fun!
Visit the showers.
It’s a long-held tenet of hostel living that nobody takes showers in the middle of the night. It’s really true. If you’re looking for a private (if echoey) location to rub up against someone, the shower stalls/room at 3am are a good place to start. You’ll have to be pretty quiet, though, since every noise carries a mile, and you might end up accidentally knocking over shampoo bottles, the soap dispenser, or the handheld showerhead.
Visit the common room.
Chances are nobody is going to be playing foosball at 4am either. You run more of a risk of being surprised by returning late-night revelers, or being given the stink-eye by the nighttime desk person, than if you’re someplace less…communal, but at least the common area usually has couches, hammocks, or other soft things to snuggle up against. Not recommended in strictly religious countries or when the desk clerk is somebody’s elderly grandmother.
The roof, the roof, the roof is on fire.
And so can you be if you head upstairs — many a hostel has rooftop access for the intrepid few who like to see the stars. Sometimes hostels will rent it as a last-ditch resort when all the rooms are full, so there might be enough space for some sleeping bags or a tent already.
You can usually find roof access by just climbing as high into the hostel as you can go and looking for the door or stairs. I once spent a lovely evening on a hostel rooftop in Marrakech with a small fire barrel and a couple of Canadian tourists. No, we weren’t getting it on, it was just a nice place to spend time.
The dorms can work in a pinch, but be very, very quiet.
Only jerks have sex in a bunk bed. Repeat, only jerks have sex in a bunk bed…when somebody else is in the other bunk.
I was once woken up at 4am every. morning. by the guy in the bunk bed above me reshuffling his entire mattress/pillow situation to sit in meditation. Imagine how irritating it would be if you fell into bed, exhausted after a long day of travel, only to be woken up an hour later by squeaking, moaning, and muffled laughter that shook your entire bunk like a boat on the high seas. Now imagine that happening when you have to catch the first bus of the day the next morning.
Don’t be that jerk. Try to avoid the bunk beds if at ALL possible in favour of smashing yourself into the closet, blundering into the bathroom, or lying on the floor. And really, if you don’t have any other option than bringing a new sexytimes partner back to your dormitory floor, maybe you should just wait until the morning and get a nice private room somewhere instead?