<human>: Summarize the given text in a few sentences.

So I have a pair of pants that I bought about 4 years ago for running. I ended up not wearing them much because fuck running. Well today it was cold in my apartment so I put them on since none on my other pants were clean. I was standing and talking to my girlfriend since she just got off of work and I started fiddling with my pockets. I felt something in my left pocket but thought it was just part of the pants (it wasn't just part of the pants). I pulled this unknown object out and my girlfriend asked me what it was. I thought it might have been some built in bag they have to put your phone in while you run. Jokingly, I said, "Looks like a pair of panties." Turns out after unraveling it that it was in fact a pair of panties. I then go into panic mode trying to explain to my girlfriend why I just pulled panties that weren't hers out of my pants. I honestly have no fucking clue where they are from. I'm leaning towards somebody putting it into the pocket of the pants in the store to sabotage an innocent man.  It's been 2 hours and my girlfriend will finally talk to me about it.
<bot>: Pulled panties with unknown origin out of my pocket and my girlfriend won't talk to me. Should check my pockets more often.