My penis is 6" long and 6 1/2" in girth, cut. When I was growing up I used to slide my soft penis into the tube, and could just grasp the tip of my head to pull it through. Then, as I got hard, the tube would get tighter and tighter on me, and then the spiral seam of the cardboard tube would start to tear at the base and then would split open the whole length of the tube, kind of like those tubes of raw dough that pop open when you crack them against the edge of the counter. It felt so fucking good!
Used a toilet paper roll to masturbate when I was a teen, but has not fit for a very long time. My cock is too thick, and if it did fit inside it would stick out a little more than this cock did. I am 6.5 inches hard.