It depends on what is going to happen.
Apart from a thorough shower with lots of soap and hot water (something I recommend for anyone engaging in intimate body contact with another person, gay or straight), if I'm not planning to have butt sex with my boyfriend, then I'm done.
If anal sex is on the menu, we have a simple device to spray water in our butts and then expel it in the toilet. (This is known as giving yourself an enema.) After repeating that process a few times, the butt is not only clean on the outside but most of the way inside. ;-) It only takes about ten minutes and doesn't hurt or feel uncomfortable (just a little weird the first time). Typically, this is something we'll do before/during the shower.
As for lube, most people use it on-demand during sex. There's no "pre-lubing" process. My bf and I keep it close by, and when we think some lube will help, we grab the bottle. (By the way, half the fun of lube-- and again, this goes for gay couples-- is helping your partner with it!)
Best wishes.