-1. Dogenzaka has it.
As for the tag itself, it needs some sort of definition and/or heavy cleanup.
It's currently a mix of..
1. A few direct parodies references to the infamous internet shock site/meme.
2. Several images of girls two-handed spreading their anuses.
3. A few pictures of one-handed anal (and vaginal) spreading or horrible large insertion.
4. 1 pic of two-handed vertical vaginal spreading.
5. Some strap/tentacle spreadage
6. Yukari spreading one a gap with her hands.
Someone who cares, feel free. Personally, I find myself incredibly demotivated just looking at the thumbnails.