Most Helpful Guy
First of all, note that statistically, as a human male, he is up for a casual hook up by default.
Step 1: "do you remember me from that party? I was wondering if you wanted to grab some coffee" or something similar.
Step 2: during conversation, talk aboit an actvity that requires going back to his place (ex: "I love just chilling and watching a movie" or steer the conversation such that he talks about his place and say you'd love to see it in person).
Step 3: while at his place, on a sofa or similar, sit a little too close, and increase body contact.
Step 4: if he hasn't initiated base-rounding yet, just blurt-out-ask if he wants to kiss.
Step 5: start taking off clothes and do sex fun.