I'm Just Renting -- Can I Have Sex?
If you have just rented an Airbnb and you would like to have sex with your partner, it is entirely within your right to do so. Be mindful of noise levels to some extent, but otherwise, feel free to do whatever you want to behind closed doors -- after all, you have paid for the room, so you should be able to treat it as though it is your own. If you are renting a place with your partner and you want some quick action on the old bed springs then the honest answer is that yes, it is ok if you want to go ahead and have sex.
By taking a place at an Airbnb you are really doing someone (the landlord!) a favor anyway, so whatever you want to do there should be ok within reason. If you want to have sex then you can because there is no law against it and no house rules that say that you can't. The fact that they allow couples should mean that they are going to assume that you are going to have sex there, so why not go ahead and just do it anyway? So long as it is not bothering anyone it is absolutely fine to have sex at an Airbnb. Besides which, the business model that they use may not be around forever anyway; some cities are already starting to think about limiting their use since they are affecting the buying and renting markets adversely, which is not good for a city's economy. So while you can still get such a thing as an Airbnb, you may as well treat the place however you want, so long as you pay some attention to the house rules. Before too long there will most likely be a backlash against these kinds of renting schemes, but until they face new regulations, sex at an Airbnb remains a right that anyone can enjoy so long as you are respectful and you are not bothering anyone unduly. Keep that in mind, and have fun at your Airbnb!