You can combine pumping and MOSRED to make better use of your time.
Pump tubes are polystyrene, acrylic, or polycarbonate; they're about equally transparent (90 to 92%) to the 660 to 850 nanometer light from the MOSRED.
Pulling your shaft out in the tube loses ~10% of the MOSRED's intensity, but lets it get to the entire length of the shaft, not just what's visible when flaccid or turtled.
Pump tubes are polystyrene, acrylic, or polycarbonate; they're about equally transparent (90 to 92%) to the 660 to 850 nanometer light from the MOSRED.
Pulling your shaft out in the tube loses ~10% of the MOSRED's intensity, but lets it get to the entire length of the shaft, not just what's visible when flaccid or turtled.