Being cranky as if on their period, or actually on their period.

Made from the fact that some people wear sweatpants when on their period and are cranky when PMSing.
Example 1:
Person 1: (chatting profanity online)
Person 2: are you wearing sweatpants today?

Example 2:
Person 1: (playing Call of Duty) DUDE WTF CAMPER NOOB stfu gtfo!!
Person 2: It's like you're wearing sweatpants whenever you play COD.

Example 3:
Person 1: My mom gets pissed off every time I do something lately.
Person 2: She must be wearing sweatpants.
by 12dan4 December 12, 2011
On November 15 every boy needs to wear grey sweatpants to raise awareness for all single ladies and the day of asking them out.
Boys wear grey sweatpants and ask the girl, boy or person you like out on a date.

Girl: wow he is wearing sweatpants I wonder if he is going to ask someone out.
Wear grey sweatpants day needs to happen
by Yo need love November 4, 2019