Haven't had the joy of the anal probing, but have had the full on deep throat experience.
I came back from holiday a few years back with horrendous chest discomfort: thankfully only acid reflux. Had to get the camera down the neck so off to out patients one fine morning. First decision: sedation or throat spray? Sedation meant longer there so I'll have the spray please.
Off to a room and they sprayed the most disgusting tasting stuff in my mouth: avoided the vomit reaction so far. Next step: down on the bed lying on my side and they start feeding a firehose in. After a minute, they realise the camera's on the blink and need to swap it over for a new one: now wait a while before we go back to the start of the firehose eating contest, only now the throat spray isn't quite so effective. Then came the inflate the stomach joy with the accompanying involuntary belching and horrendous gagging. All the time, there's only a blank wall to look at: nothing to try distracting myself with. Couldn't even see the Nurses, who were reasonably interesting if I recall correctly, not that I felt I was showing my best side during our time together.
I have no concept of how long the whole affair took, but it seemed an eternity. On the way out, I saw the lucky ones who'd been sedated being wheeled back into the recovery room with no recollection of the event at all - if there's a next time, knock me out please Nurse!