I know that you can fit creatures inside the bag and that the bag has a limited amount of air, with part of the Bag of Holding's description reading
"Breathing creatures inside the bag can survive up to a number of minutes equal to 10 divided by the number of creatures (minimum 1 minute), after which time they begin to suffocate." (DMG, pg. 153-154)
However, the Air Genasi have the racial trait Unending Breath
"You can hold your breath indefinitely while you’re not incapacitated." (Player's Companion- Elemental Evil, pg. 9).
This would imply that an Air Genasi could casually sit in the bag for hours while holding their breath. If so, could a party in theory smuggle a group of Air Genasi inside a Bag of Holding?
I do want to note, however, that the Bag of Holding does not specify that a creature inside of the extradimensional space can try to force its way out, so would putting someone in there even be a good idea?
Best Answer
If you can fit it through the opening, you can put it in there.
This would effectively make your Bag of Holding a wonderful trap/container for your Genasi.
As for opening it from the inside, rules do not state you can or can not. Lots of people have asked this before, but I personally do not feel that you can open the bag from an extra planar space because you aren't technically inside a bag, you're actually on a different plane. To me, that means you can't manipulate the opening of the bag.
But that's my opinion on it.