Shouldn’t need to do a sleepover. 20+ years ago I had a “nocturnal penile plethysmograph” test. It was a small battery powered module that strapped to my thigh, with rings that wrapped around my penis. Every few seconds the rings would gently contract, with resistance (indicative of an erection) being recorded by the device. This way they can document an entire nighttime of erections, all while you sleep at home in the comfort of your own bed.
If the op’s doc is smart, they’ll make this one of the first tests, as it’s noninvasive and pain-free. I just wish someone had done that for me before they did all the other stuff: