The story behind this play is actually quite fascinating — the person in the picture was born with webbed toes on their right foot. As a teenager they wanted to normalize this, so using a razor blade they started cutting the web slowly with a razor blade, using pressure to notch in the web. Bleeding was relative minor. In any case, they discovered that they enjoyed this activity and found it exciting, and started doing it recreationally as well with other, unwebbed, toes, and are considering an amputation.
Anyway, I always find it very interesting to find out what the catalyst is that causes people to stumble upon, and then discover that they enjoy, heavy play and modification.