Some days ago I was playing at the BC-Spawn and we noticed two Bugs, both with /sit.
One of my Friends was sitting at the Floor and sent me a /tpahere. As i accepted I didnt get teleported to him, I was teleported under him. He was sitting above a hole and i got teleported in it. It was a 2x2 hole, so there was not much space, but we found that kinda funny and sat down in that whole and talked a bit. But as we left the sitting Position we got one block lower in the Ground. It took us a while until we noticed, that we can sit again in the Ground. As soon as we did that we could see the Caves in the Ground. We were able to repeat the "/sit and leaving sitting Position"-Thing over and over again, so that we can get deeper and deeper into the Ground.
Today I remembered, i got a home in that hole and showed and explained that to VicKetchup who has filled the hole now. I found These glitches as abusable and decided to post them here on the Forums. I hope you know what to do or how to handle this.