Sexish stuff...

So a small group of my friends are going up to a cabin for the day and this is the first time without any "real adults". The boys might bring some stuff to smoke or drink but I'm not completely sure... but anyways, the reason I bring this up is because the mood will kinda be set. I like one of the boys (I'm almost 20 and I've never been kissed) and I'm hoping if the mood is right we can start making out (at least lol) but how do I send signals to him without over stepping boundaries?!?!