Okay so like this
is what I managed to gleam from other blogs but this is what I know and write with:

Adult omegas in
heat is kind of like a someone on their period only omegas have
strong sexual urges during heat which most people don’t have while
they’re actually on their period and bleeding and there is
something called slick produced to make sexual penetration easier.

Heat is the body preparing for babies and resisting the urge to mate
with someone can be… painful? Or leave one unfulfilled as far as I
understand though one is fully capable of not mating during the time.
Oh and an omega in heat apparently puts out pheromones to attract
alphas too and get a mate.

Each writer
sometimes tend to put a spin on this part though.

I generally just
think of it as a period with the slick replacing blood but with
strong sexual cravings where scent can be helpful to calm someone and
a bonding gland exist. So I tend to add cravings, bloating, pads
annoyance and so on for the pre heat stuff. But yeah, it be easier to
check with omega blogs about this since this is just me whinging it.