Given its sci-fi setting, Futurama has plenty of material for smart gags, so it's a little surprising how many dirty jokes Futurama got away with during its run. Not all the dirtiest jokes on Futurama are explicitly sexual in nature, as creators also managed to sneak a fair amount of drug references past the censors. Sometimes, they even combine the two (watch out for Bender when he's been "jacking on").
Matt Groening is no stranger to adult jokes — there are quite a few in The Simpsons — and it seems he kept those muscles flexed when crafting Futurama. While his shows aren't considered nearly as crass as Seth MacFarlane's Family Guy, that doesn't mean Groening isn't capable of capitalizing on low-hanging fruit.