Let's just say some features like this can lead to a secondary feature or more and people may be reticent because in the past they lost features as they were spoken about and got taken out by the then Devs. But the /sit like being tiny has been around that long it seems to be an accepted feature. It can be done almost anywhere.
My particular way is type in /sit which is part of the slash command set. Click in the open window out of the chat box so the chat window is not affected by anything typed, directly anyway. But we will make it affected after we jump. At the top of the jump (guage that yourself with practice) hit the return key twice. The first hit puts the cursor back in the chat window just like an empty chat window with a return puts you outside the chat window. The second hit on return carries out any chat in there. Et voila you sit in the air. But it doesn't have to end there.
Type /sleep in the chat window and hit enter once. You stand up in the air. Type /sit in the chat window and press enter once and you temporarilly sit then go back to standing on the ground. This last action happens no matter if you sit or stand in the air. You can sit on the ground too if no seats exist or are available. If you click on one of the virtual maps whilst sat you get turned into a Mario Cart. A person sat who can move around like they were on a cart, by using the normal forward/back actios and CTRL to control speed.
This Mario Cart can be done another way but I cannot and unfortunately will not mention that one. Hidden gems like these used to be passed on to others and were part of the fun that kept people here longer, especially new people who saw what was happening around them. Unfortunately they were removed by over zealous people.
NOTE: My nick and image are from a company. That company allows people to use them both as long as they get permission and a licence. I have that and a certificate to prove it.
"These are not the Druids you are looking for..."