Catheter play

Hello, I am pretty interested in the catheter play, do you have some advice for the first time what kind of catheter i could usd on my self? Lubricant? And what kind of liquid i could use to fill my bladder via catheter?

Sorry for spoiling your turn on, but don't fill anything in your bladder. The inside of the bladder is sterile and must remain so and bladder infection is something very serious.
This is why installing a urinary catheter must be done using the right protocol.
That said, full catheterization (rear and front) when done appropriately for total enclosure and mummification in latex or duct tape is a real turn on for me as it allows long duration encasement.

Yea, bladder cleaning is super dangerous.
I have played with catheters before, and got lucky in that I didn’t get an infection.