Actually, the first time turns out badly for many gays. Many tops are only looking to score once and then abandon the bottom after a "quick one."
The longer you know the top, the better the outcome.
Be assertive, try different positions if necessary.
Best possible outcome is a monogamous LTR (long term relationship.) The fewer partners you have, the lesser the chance of catching a STD (sexually transmitted disease.)
Using a condom is "safer sex," there is no such thing as "safe sex" with anal.
Things to watch out for: putting the condom on backwards, having the condom "slip off" or (with a cheap or old, expired condom) having the condom tear.
The most dangerous time for something to go wrong with a condom is the first time; if the top is also a newbie, take extra care. Practicing ahead of time could save a lot of grief.
Beware of being swept up in the moment and forgetting the condom altogether.
And if the top refuses to wear a condom, it should be a deal breaker. Since the top and the bottom are both equally at risk for AIDS, the top refusing to wear a condom could mean he doesn't care about catching AIDS because he is already HIV positive.
By the way, blow jobs result in almost zero AIDS transmission.