First time w/ FWB advice

Sorry about the essay but....
Right so I've been texting this guy from college, it started off after we kissed on a college night out and now it's gone onto nudes on snapchats and what not! 
We spent one night together at a house party but the furthest we went was some grabbing etc and I gave him a wank! 
Ever since, he's been trying to plan a night together and it's looking like it's going to be on Tuesday! 
I'm a virgin so I don't really know what to expect! I'm not scared of it hurting but is there anything I should/shouldn't do beforehand!??thankssss