Well, since the rest of the world seems to think that gay men only really think about sex we might as well start with that. Sex, sex, sex, let's get the shy retiring bit out the way, most of us have times we really want it, many have times we're not that keen and all of us have times when a good book (or in some cases a cup of tea) is infinitely more attractive.
So what are the health things that you should think about. First thing is, have the sex that you want and feel good about it. This means if you don't want it, say no and walk away. And if you're getting it , get it the right way, explore the things that make you feel good, experiment with ways to ask for them, have fun. All of us have sex which is dissapointing every now and again and instead of making you feel bad about yourself just think about why it was bad and file it under useful information. Sex should be enjoyable, don't be afraid to have fun with it and laugh and play. If you can, and don't worry lots of us can't, talk with your partners and your friends about your sex life, share your thoughts, your fantasies, your concerns and worries, you'll soon find that you're not the only one that has those thoughts.
Before we move on though we should touch on what to do if things go pear-shaped. If somone forces you to have sex then find someone to talk to about it, you don't have to go to the police but you should get help and support. Its estimated that over 700 men a year are raped in the UK, so if it happens to you, here are some of the places you can get help and support and information:
The second thing we should discuss while we've got your attention and your mind is on the sex track is safer sex. There are lots of websites which will give you good, upto the date information about safe sex and we're not going to rehash it.
The main thing is get used to using condoms, (even if you think you're only ever a bottom – with the right man, everyone has versatile moments!), that means play with them when you're on your own, try jacking off with one on. Sometimes it helps to put a bit of lube on your penis before you slide the condom on, but not too much otherwise it will slide off and that's a whole different discussion! Think about how you'll work putting a condom into your sexplay, it shouldn't have to be something you have to stop and do that breaks the mood, make it part of the seduction, sliding it down his penis or dropping it onto his chest and lying back making it obvious you want him but only in the 'safe' way, just some ideas to get you started…and always use lots of lube…it will make it better for both of you…But sex isn't all about fucking and loads of gay men have great sex lives without fucking, explore what works for you and enjoy it, different things will work with different people.
If you don't use a condom or it splits, slides off, tears or something else happens then you could consider post-sexual exposure prophylaxis (PEP). This means going to a sexual health clinic and seeing one of the doctors and then taking a course of tablets for a month to reduce your chances of catching HIV.
There's more information on sexual health services (it's a bit london centric but there are links to local services) at:
The NHS Choices website has a lot of information on sexually transmitted disease so easiest thing to do is click the link and although it's a bit heterosexual in its focus Condom Essential Wear has buckets of information on condoms and a really useful local clinic locator gizmo.