The glute bridge is almost the same as the popular hip thrust but your back is on the floor instead of the bench. It's a great exercise for glutes.
But the trouble with bilateral (two-legged) glute bridges is that because it's a relatively short range of motion and you're calling on the strongest muscle in your body – the glutes – to move the load, you can really pile on the weight, far more than you can deadlift.
That's not a bad thing, but as the loads get heavier it can get pretty uncomfortable for the neck and hips. And there's a tendency for your body to slide backwards on the floor as you bridge up. So try it with one leg.
Single-Leg Barbell Glute Bridges
Even though the loads with the single-leg version pale in comparison to what you can handle bilaterally (less than half), the contraction feels even bigger. Moreover, because the weights are lighter, it's much more comfortable on the neck and hips, and loading the bar isn't nearly as big of an ordeal.
It can be awkward at first to get the barbell centered on the hips. It's helpful to start the set with a bilateral bridge and then lift one foot once you're already in position, as opposed to starting from the floor on one leg.
You can also start with eccentric single-leg bridges. Just bridge up with two legs and lower yourself down with one.
Eccentric Single-Leg Bridges
This eccentric (negative) version is both a great progression to work towards single-leg bridges and a great exercise in its own right if you want to overload the eccentric.