Problem keeping flaccid penis in proextender

My flaccid length 90 percent of the day is around one and 2 inches and the other 10 percent its around 4 and 4.5 inches.
My problem is firstly for me to wear the extender i need to get semi erect as to then put it in the noose and lengthen the rods if i feel the need to do so.
by this time my penis isnt erect but soft and fuller than it usually is and in a stretched state to .
I then would normally check again around 10 minutes and see it has shrunk substantially and looks extremely thin as it is stretched.

Really all im looking for is how i can keep my penis full enough to take advantage of the extender and not slip out like it does
BTW the extender is a knockoff version