So the beer can is 3/4 filled with beer ? And there are 2 holes at the top ?
What I do is pour half the beer out (for enjoyment) then add spices in the remaining beer ,whatever strikes your fancy. I use seasoned salt, rosemary, and dried onion.
YMMV.
It works better if you drink 3/4 of the beer and leave a 1/4 in the can to steam...you don’t waste as much beer!