There are some particularities when it comes to sex in hostels. First of all, is to prefer wild sex and quickies instead of long foreplay. Ask about the local habits, and if you see things like these, go away!
So, as a foreplay, I would sugest dance, touch, drink and speak about all possible things. Now, you have the partner, the labour is half done.
Then comes the most difficult part: finding the place. I see following possibilities:
-go simply in the dorm, and try to make abstraction about the others. Do not screem, and do not expect that the others will not disturb, you may not ask from them such things!
-check the laundry room
-check other secret invisible corners of the hostel, if you know them, or your partner does. You can ask about them the crew, but I doubt about the results(exception: your partner is a member of the crew)
-avoid the bathroom and the shower. In my opinion, it is much more embarasing than the dorm. In any minute someone could come and ask imperatively to enter.
-take a walk outside the hostel, maybe you can find a park, a beach or a bunch of trees.
-check the roof, the basement, the heating room
-hire a car
-go to a hostel
if not, come back tomorrow on journeyetc.com and see what's new :)