Cloacal Opening - Is this normal?

[Bogertophis]

...and do have a separate enclosure without any substrate for feeding...

It's best for a snake's concentration on eating if they are fed where they live, not removed to another container. That handling will put many snakes off eating entirely, & while you might be getting away with it now, it's not a good practice. (trust me, I've heard all the "reasons" ppl give for doing this, ie. "cage aggression", yada yada) A snake that is hungry is way more likely to bite you when you handle it to move it elsewhere, & even MORE likely to bite you when you try to put them back, as they stay in 'feed mode' for hours or even a day or more. Your warm & wiggling hand will not always be respected as part of you, & not prey.

BPs are snakes that are easily put off eating, especially as adults (around age 4), so what works ok now, might set you back later on. They are also "ambush-predators" by nature: they like to peek out of their hide in the evening & wait for clueless prey to stroll within reach. By moving your snake, you totally disrupt their natural instincts- & the only thing that picks up a snake in the wild is a predator that's about to eat THEM! Fear is not helpful to a snake's appetite.

A much better way is to wait for their behavior (as just described) to signal their readiness to eat, then offer f/t prey from tongs with a slight jiggle to simulate "live". The prey must be properly thawed & have life-like warmth -many here use a hair-blow-dryer to give it that "finishing touch". Feeding live prey, sooner or later your pretty snake will get bitten & potentially maimed (some lose eyes, & others die from resulting infections, always harder to treat in our cold-blooded pals). If that happens, even assuming he survives OK, you'll have the pleasure of seeing his scars for years to come, knowing they could have been prevented.

BTW, you can put something like a piece of cardboard or a large plastic lid over top of the substrate, ahead of time, near where your snake will feed, to help them keep substrate out of their mouth. A little bit won't usually matter anyway, but best avoided, as snakes have no enzymes to digest branches or other wood products.