If you think online sex games are all crappy flash games, you should guess again. Thanks to the good folks over at Nutaku.net, you can enjoy many high-quality browser and mobile games that are free to play, as well as premium, downloadable games.
Registration is free and each user gets a bonus 100 gold ($1) but can buy more to purchase games. There are 25 free sex browser games and 12 free porn games for mobile devices. Furthermore, you'll find more than 100 downloadable titles that cost $5 on average but can go up to $45. There are lots of familiar genres present including visual novel, adventure, RPG, JRPG, dating sim, puzzle, casual, card, strategy, minigame, etc. As mentioned already, these are not your typical flash games that you find on dodgy sites. A lot of work goes into each one, so you can expect quality both in artwork, story, and gameplay comparable to traditional video games. There's also a unity plug-in that will let you play real 3D games from your browser.
As a site with premium content, Nutaku.net looks and works great. Layout and design are well thought out to offer the best user experience. You can keep track of game events, browse all titles, and create your public profile as well as contact and follow other members. To get extra gold, you can complete missions or get referral bonuses.