Back in the days when Jacquest Cousteau was traipsing around the world and none of Lloyd Bridges kids had yet to start shaving, I was taught to put my gear on with an overhead toss. Ah, the drama, the style. Slap the regulator in your mouth, caress your BFK for good luck and it was time to get wet. We bad.
Now, older and working on wiser, the lack of control inherent in that method makes me nervous. Ah, the flying gear, the divers climbing over each other to avoid being clobbered. With 349 pieces of doodaddery hanging off of the rig (are we sure horse collars and rocks weren't better?) you're bound to end up explaining to someone that the regulator wedged in the crack of your ass is the latest iteration of DIR routing philosophy while your BWRAF your way through a buddy check.
When I can, I'd rather put gear on while in the water. If that's not appropriate, stand the rig up and sit down into it; if that's not appropriate, slip into it like a jacket. The last choice involves too much twisting and turning under load, but at least you have better control.
When is someone going to come up with gill implants?