Ok so I get this from being a top and bottom side of things
When I first started playing I knew nobody gay! I didn't have a gay friend. I wasn't out to my parents and everything I had seen was through porn.
My first time topping I spoke to the guy for ages and we met up once and had some foreplay. A few month's later we met up and we went to his house. Being a top you Don't need much prep but make yourself smell fresh especially if the bottom is gonna go down on you. Help the bottom loosen up to. Rimming. General stimulus to make the bottom horny helps. Discuss the use of protection. If it's gonna be a random you might want to use a condom or be taking prep first. Buying condoms isn't as embarrassing as you may feel and it's good to have some whether you're the top or bottom so you're never left in the lurch.
Apply lube like a mother tucker!! Lube the condom. Lube the ass. If the bottom is turned on don't be afraid to use your fingers and maybe push some inside too. Take time to listen to the bottom any harsh sudden sounds may mean it's too fast or not enough lube.
Bottoming. There's many different ways and you need to know your body.... for me I don't eat anything particularly heavy the day before or of. Keep it light and simple. Some people like to douche before meeting up as it helps to feel empty and you know they're won't be anything on him when he pulls out.
Make sure you smell nice. Im not talking cologne or deodorants give your ass some attention with a nice body wash. When it comes to playing make sure your ready. The first time you're going to be tight and the first muscle of your sphincter is going to hurt as it stretches this is why you might want to try fingering yourself first or using a dildo or butt plug so youre used to the feeling of something inside.
So like I said. The pain at the beginning is ok. Take time let your muscles relax and keep breathing. Keep an open line of verbal cues or communication of how your going letting them know if it hurts to much, keep going, slow down ect ect.
If the pain is beyond bearable then something isn't right and you may need more lube or you aren't relaxed enough.....
These are just some tips and they aren't the be all or end all. If you want any other advice I'm more than happy to chat
Xoxo cuckboy96