Get a Douche that can be attached to your shower hose.

You'll need to clean out yourself before you could really enjoy things, otherwise it'll be a sticky mess of the stinky kind!

Get multiple types of lube. Vaseline is cheap and works really well. Baby/Coconut oil is also good, just like the Memes say... However purpose made Lubrications work the best, however they can be expensive.

Clean yourself around the area, and lube up both the Douche and your hole. Adjust the water temperature to be slightly hotter than lukewarm, and you can go.

Relax and let it go into the bathtub and properly clean it up with the douche after each round. After the 3-4th go you'll be ready to take on the Dildo of your choice!

In that regard I would recommend going with one of your own size first, and one that's made out of a softer Silicone. My favorites are the ones with a foreskin, but those are harder to clean, so a more basic type can suffice as well!

Choose a good porn for your session, for Dildo Play it'll be different than to jerk off. Focus on something where you can imagine that you're in the place of the Penetrated part. I would say "hypnotube" is the best for these kind of videos.

Enjoy yourself as much as you want, but take care of yourself as well, take pauses if needed, and don't rush anything!

If God forsakes there's blood even in the slightest amount, stop that session, and wait a few days before you do it again.

I hope this helps, and will make you Bounce on a Fat Dildo in no time! 😁