Sounding is a big thing for me. Here's some stuff I've learned over the years.
- Go slow. Breathe.
- If it stings, slow down. If it hurts, stop.
- Wash everything before and after, every time.
- Wear disposable gloves if you want to be super clean.
- Use STERILE lube such as Surgilube. Urinary tract infections are not fun.
- Start with a Pratt urethral dilator set or a silicone
- Drink a lot of water so you are hydrated. I also like to take a piss after my play session to help flush out the leftover lube.