I spend a lot of time in hotel rooms, usually with a porno channel. Over the years I have developed the following simple but effective technique.
Use whichever method you like best to get really hard and wet. Get close to orgasm and start 'edging'; getting close then backing off, getting close and then backing off. Once you are aching and you stay hard, even without the hand contact, start saying what you are thinking about out loud. (Be careful, if the walls are thin, your next door neighbour usually starts thumping, and this can be a bit like a cold shower; unless of course you are into exhibitionism.)
I think that most of us fantasise in colour and full quadraphonic sound, so this method gets you to say it out loud, which is surprisingly difficult the first few times. What you say depends entirely on what turns you on, but, when you are used to it, you can bring out your most secret desires and it gives you a real kick.
Obviously, you can do this anywhere, in any circumstance. I find that I enjoy being the porno film director, complete with temper tantrums when the actor/actress don't do what I tell them to! I also enjoy taking it in turns to imagine that I am the actor and then the actress (but that's just one of my kinks).
Just a word of warning. There comes a time when, no matter how turned on you are, you just can't stay hard any longer. The first time that happens is a real let-down. Once you know the symptoms you can make sure you come before it's too late. If you miss the chance and it is at night, go to sleep and the next morning is just as good.
I hope that this adds to your armoury and that you get as much pleasure out of it as I do.