Same experience with me, my son held the clutch to the floor, but as soon as I started the bleed it stayed down by itself, and I had to pull it up by hand after it was over. Totally normal.
Pedro has a good tutorial on it as well on his site and it documents that same issue:
Bleed the Brakes & Clutch
Steve
PS good for you, that clutch slave cylinder bleed screw is a !@#$%^ to get to, at least it was for me
