There's a handy "How to Play on Android" above.
I just use itch.io but I make it so it only shows me android games.
I guess Newgrounds also works, but not perfectly.
I also use Google to find forums of people suggesting games, since that's how I tend to find really good and finished games. You can also follow groups on social media sites, look into hashtags, or follow people that share these games.
There's many games that are pc only but can be played on mobile if you used Joiplay. If you have a computer but want to play on a portable device, you can use steamlink to remotely control your computer and play a computer game (tip: PC and Phone should be closed to the router for best performance. You can also just buy a cheap router that you can carry anywhere and both your pc and phone can connect to)
You can find some mobile games on my collections on my profile.
Edit: If you google search "android porn games" you will find some websites. Don't knock them until you try them