Read through all the posts here, but have had no luck answering this item. I've been getting used to a cb6000s in short stints starting with large ring, large spacer, working down through the spacers, down a ring, then through the spacers again at the new ring. I've found that ring 3 with all spacers is good, but can pullout when at my smallest. I've been able to find excellent security with ring 4 and the largest spacer and this combination is comfortable although the ring is mildly difficult to put on, nothing turns blue and I can almost forget I'm wearing it - up to 6 hours days only. I am concerned as one of the veins on the underside (left bottom) of my penis shows up very dark and almost seems to have blood trapped in it when wearing the #4 ring (and even a bit on the #3 ring). Is this normal, part of the getting used to it process or something to be worried about? Thank you for any advice.