My standing instruction to new divers is to *never* take the reg out when Ralph becomes their dive buddy. If you really start heaving, there is an almost unstoppable urge to *gasp* immediately after. Without a reg in your mouth, you're much more likely to gasp a big draw of water, which would be a very bad thing indeed.Not wanting to risk a possible fouled reg, I took it out of my mouth and and just went with the flow.
The reg can take it, and adding near-drowning to fish feeding is never a good thing.
(Oh, and RedWingDiver, I'll have to try to try the see-a-shark method of avoiding seasickness. )