Not sure this is funny in a traditional sense, but it always makes me giggle at myself and gets my bf laughing because I'm dancing in my chair.
I often get so into surfing the internet or playing online, hyperfocusing I guess, that I'll start squirming in my chair before realizing that I need to go to the bathroom. It's so bad that you have to sit still and tighten all your muscles for a minute before being able to get up and walk to the restroom.
It can also happen when I'm painting, writing or even dancing. It feels like part of me forgets or doesn't realize what's going on until it's almost too late.
I've always made it to the restroom so far so that's why it's more funny / amusing than a problem lol. :)