If you're talking about doing it with your lady, not random whore who is down, and communication lines are open, do it right. Prep goes a long way at first. A nice Brazilian wax and home enema kit will keep it clean and looking good, like it does in the movies.
Also, good lube and some a fair amount of prep time with your fingers to loosen it up. If it's something your and your lady are into continuing in the future, make sure she's enjoys it as much as she can the first time. If you go in too dry or too early, it's going to be so painful she'll never let you back there again.
Good luck.