For a girl, the chair may mean the casual dumping place of clothes you don’t want to fold.

For a guy, let’s just say there are some very questionable stains and you have to debate if you really want to sit there and how safe it is.

The act of pissing and shitting on a chair simultaneously while watching porn

When a man is leaning on the wall like he's sitting on a chair and the girl sits on him and jumps up and down...
Its a sex positon...

When you fuck a girl while she is sat on you playing a videogame so during climax you make her lose the match so she will be swearing while cumming

When you have a boner and your push your dick downwards between your thighs, adding lots of lube, your rock back and forth until you finish.

Also known as, the toilet. So named as its the most common place smartphone users update there Facebook page

When you are feeling rich in spirit, but you are too financially poor to play music chairs. Here we go round the mulberry bush... again... cuz we're really really poor... financially...