I always try to bring one at an encounter.
I used to have a vibrating one but I never saw the girl enjoying it. I'm clueless on this product.
I now have the rubber one. The hardest part is to put them without lube... man, it hurt.
And yes, I feel it's true about ejaculating while wearing a cock ring. It seems to tone down the orgasm. I always rush to remove them before cumming.