(n.) pants one (usually a guy) wears comfortably in his room or household and can comfortably have a boner in without tight resistance or any feeling of irritation; may be worn during duration of watching pornographic material or foreplay (usually with a girl) in a couch/living room or bed/bedroom scenario. these type of pants are usually one cherishes and washes about once a month.

Brazilian butt lift

girls pants worn by guys(emo kids). given the name for being so tight that it is clearly visable of when the emo kid has a boner. There for they are bonerpants

Pants that make it look like you're sporting lumber.

A perverted guy who wears short pants in public and letting everyone easily spot his erection

Pants that aren't tight at the top, so when the wearer sits down, it appears as if they have an erection.
This can lead to some pretty embarrassing experiences.

noun. Pants that use tough fabric (jeans, khakis) and constantly look like said wearer has a boner. Jeans show this the most, especially whilst sitting.