Vajroli without a catheter

Hi,
I was hoping someone would be able to shed some light on the practice of vajroli mudra without the need of a catheter. Is the use of a catheter necessary to draw liquids into the bladder?
Thank you

Interesting first post…
I would think that while it may be possible without a catheter (I don’t really know) I would say that it is not possible to learn to do without a catheter. Either way you are at risk for a urinary tract infection if you are not very careful. Why does this interest you?

I’m interested in several ways… perhaps I would drop the idea of liquids into the bladder if I had a diagram of what happens during the proceed and also what happens when one performs cycles of dry vajroli (contration of frontal PC muscles and sucking in of the belly)