it is mostly random. you should throw the chair (not drop, but actually throw, it's like holding the rmb and pressing lmb). it's better if your cursor is below center this time to aim lower like in the image. if you do like that, you'll probably throw this chair right at your feet. spam jump and you'll fly into the air. you'll probably do it many times before you succeed.
phlize, you will get flinged all the time, basically always, but randomly you can get flinged far away.
@CrazycatXD do NOT make different forums about the same thing
Before I begin to say anything, this post (at the time of writing) will not officially allow the build into speedruns but will only explain the reasoning behind the 3 big questions: Where are those runs? Why haven't the moderators done anything about it yet? Is it ever going to get added? Anyway, on