I've had the experience but not mouth.

I was giving it to an Ex in standing mish (Her on her back on edge of bed, pillow under the ass and knees to the chest) and after I came I just kept going.

I came again about 1 minute later and I practically fainted 5 seconds after just managing to get into the bed myself.

My partner said I actually fell asleep almost instantly.

It was an incredible feeling but also a wild sense of vertigo (stood up too quickly).

I think it would be even more intense if it wasn't under your control!