Congratulations! A few things to keep in mind.
First and foremost,
this is supposed to be fun. Always keep that in mind.
Prepare. Bring a box of condoms and (as pointed out) water-based lube. A glassof water and a warm moist washcloth by the side of the bed often come in handy, as well.
Practice putting a condom on yourself, until it's second nature. You don't want to be fumbling around (in a bad way) when the moment comes. It can erode the mood, and it's far too common that people say "fuck it" and start playing unsafe.
Don't do this. Ever. Make a commitment to play safe always and always.
Start slow. Take each other's clothes off. Leave the underwear on, lie down on the bed, make out while rubbing, whatever.
It sounds like both of you are virgins (although you weren't totally clear about that). If so, that's cool. Since you don't know what you like yet, be open to trying stuff out. Ask if you can try things. "I'd like to lick your ass cheeks - is that cool?" If you don't like what he's doing, say "That's not really doing it for me. Can we try (something else)?" If he's doing it too fast, too slow, too hard, too soft, too wet, too dry, too whatever - let him know. "That feel great, but could you slow down a bit?" Keep it relaxed, keep it fun.
If you want to try anal, that's fine. But remember the three things you're gonna need: condoms, lube (and lots of it), and time (and lots of it). Don't rush it. Insertion may take several minutes of inching (or millimetering) ahead slightly and pausing. Let it.
After you're both totally spent, head the shower, wash each other off, dry off, head back to bed, and discuss. What weren't you a fan of? What got you hottest? What would you like to try next time?
Have fun.
Lex
