Emma goes through a lot of jeans. The number one reason she ends up replacing them is forgetting to leave her zipper open. The denim just doesn't hold up when she gets one of her sudden "explosive erections", which tend to leave the crotch of her pants looking as shredded as her abs. When all goes well, her cock simply pops out and doesn't take the zipper with it.
A - original | B - pulsing bigger | C - w/precum | D - pulsing bigger w/precum