In the UK 'pop' is often used as verb for doing something quickly. More often used to describe going somewhere. "I'm just gonna pop to the shops, did you want anything?" But in some situations it would work with other actions. "Billy! You can't go to school in that shirt, it's got a great big stain down the front. Pop it off and I'll get you a clean one."

Pop off pants are tracksuit pants which have snap buttons down each side, this means you can take them off by pulling the front, causing all the pop buttons to come undone.

Hi, I'm not sure if this is used in America but it is used a lot in the UK. 'Pop' can be used to mean 'To go' 'I am going to pop to the shop' means, 'I am going to the shop.' 'Pop off pants' means to 'Take off pants'. The word pop has a lot of meanings and can mean several more things.