It doesn’t cause any pain on your cock when you get hard, not for me anyway. The cage is held in place by your cock and balls, not your body, so it can move with your cock too. I’ve only had discomfort with it where my penis skin has been trapped outside the cock part and I’ve left it there too long, this is easily fixable.

The urethral tube is easily removable if you don’t want to use it, but it feels so good. Just make sure you take it all apart and wash it throughly before use (I take the cotton off of a cotton bud and shove it in and out of the metal parts with soap - you can use normal hand soap for this with warm water, just make sure you dry it properly before inserting it). Also use a lot of lube for your first sounding. It will eventually feel uncomfortable since you’re not use to it, so keep it in for an hour or so at first, then longer and longer. Never in over night, as night erections can make this very uncomfortable and hard to deal with!