Hidden Sex Games

Sex in The Sims
First make them really like each other with lots of talking, hugging and kissing. Then get the love bed (the one with the big heart).Make one of them "vibrate" and then get the other one to play with them.

Sex in The Sims 2
You need to have a strong relationship (80+) between two unrelated Sims of different genders. Find a double bed and get them to relax on it. Then get one Sim to try the "Woo Hoo" command on the other one. You can also try "woo hoo" - ing in a jacuzzi. If you want to get pregnant select "try for baby". Sims can apparently be homosexual if you show them how. Teenagers can't woo hoo.

Sex in GTA San Andreas (Hot Coffee mod)
The Hot Coffee Mod adds a new set of missions for the main character CJ to play through. These are dating missions that CJ plays with one of his girlfriends. If you play it right you can end the date with some steamy pixelated sex.

Hot coffee mod for PC

Hot coffee mod for xbox (requires mod chip)

Note: If you have a copy of GTA San Andreas that was manufactured before the fourth quarter of 2005 or these mods will not work. If you have a PC version and you have updated it the mods will not work either as one of the patches disables the super secret code.

You need a Gameshark cheat device before you can enter these codes.
Hot coffee mod for PS2 (cheat codes)