Definition: In this task, you are given a Reddit post as a text. Your task is to generate a title for this text. The title should start with "TIFU by", followed by a situation that caused humor. The title should contain 7-12 words, ideally.
Input: Text: happened earlier this week.

for three months i've been dating a girl who i'd been friends with for a few years prior.  as such, things are great.  we're both on our college swim team, so we have a lot of the same friends.  comfortable with each other, not a lot of awkward "getting to know each other" things.  its fantastic.

so its exam time and she needed a study break.  since i'm in grad school, i've been working for home and decide we should go for a drive.  

while i'd been working that day, i started pacing my room and saw some lace.  i don't own anything lace-y.  so i reach under the foot of my bed and pull out a thong.  oh dunkster91 you sly devil you, leia* forgot her undies one of the times she slept over.

i brought them with me for the drive.  we're making small talk, i'm letting her de-stress.  it can be rather mind-numbing to spend all day on campus for days on end, so i just let her ramble a bit.  eventually we come to a break in conversation and i ask if she's forgotten something at my house recently.

she starts guessing what it could be.  quickly she realizes its something not-pg, but can't quite guess it.  "panties" i finally answer.  she then tries to figure out when it happened, maybe after we got back from the team trip.  "you definitely weren't wearing a thong on the plane" i respond.  "maybe it was after our formal?  its pretty nice and i don't remember seeing you in it, so it must've been one of the times i was drunk/tired/it was dark".

giving up, and without her knowing i've brought it with me, she says to just toss it.  the cheap scotsman inside me thinks this is ridiculous (additionally i know i brought it with me).  "throw it out?!  that's silly!  here you go!"

she takes them, inspects them.  silently, she turns to me.  "dunkster91... these aren't mine."

dread.  panic.  escape.  can i somehow get out of here without her knowing?  probably not.  mind racing, i determine who's they are (one of the few times not having an active sex life has helped me) - my ex, a friend of a teammate of ours, from back in **may**.  

somehow throughout the entire summer, fall, and winter, including two trips requiring substantial packing, i've failed to notice the panties of my exgirlfriend lying beneath my bed.  and i gave them to my current girlfriend.

needless to say, they were deposited into a garbage can at the nearest gas station.  thankfully, leia* took it well and laughed it off.  but i'm never going to get to forget this.

*obviously not her name

tifu giving my girlfriend a thong that i thought was hers, but was my ex's and had been under my bed since may.

TIFU Returning Panties to my Girlfriend (slight nsfw)