When an Omega and an Alpha are friends people tend to tiptoe around them, this is unsettling for Hinata and Kageyama.
In omegaverse there are three subgenders:
Alpha's - are generally stronger than the other genders, they go through a 'rut' where their desire to mate takes over them and they can be extremely effected by an omegas heat pheromones, suppressants are used to contol their ruts.
Beta's - Are generally normal, they dobt go through ruts or heats but they are less effected by omegas pheromones than alpha's.
Omega's - are generally weaker and more fragile and tend to be smaller than betas, male omegas have a womb inside their anus allowing them to carry children, every three months an Omega would go through a 'heat' which is similar to an alphas rut, they become more sensitive and wet than normal and more likely to get impregnated during this time.