Has anyone asked for company shares / equity in their MEP firm?

Been part of a smaller company since graduating college; and now have a very active role in decision making, hiring, training, BD and client relationships. We started with 4 people; and are up to 12 and with two owners (50/50 ownership).

They've been great with pay raises and bonuses; however this year I'd like to ask for a stake in the company. Unfortunately I know nothing about how these types of conversations go, what a reasonable percentage might look like; how payments are made, etc.

Has anyone been through smoothing like this? Any tips or ideas of what to expect?