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: this happened not 30 minutes ago. just to clarify, i'm the mother (not that it makes  much difference in this fu, but most people assume i'm male)
to set the scene i have a 13 year old daughter, she's into makeup and nails and has been ordering various paraphernalia off ebay to do her nails. today a parcel arrived in the mail after school and she excitedly opened it and it was an automatic nail file. 
after spending 10 minutes working on my nails, she needed another client.... she sets her sights on her 11 year old brother. he is very tolerant of female grooming as he is the youngest and has 3 older sisters, many times he's been 'made over' and had his toe nails painted. so offering up his finger nails for his sister was no different. 
while the grooming was taking place i was doing various mother duties around the house, then i hear a commotion and look out the door to see my son giving his sister the double bird, in fact holding it right up in her face. i called him over and tell him that is not acceptable behaviour. this is where the fu happens, he's trying to talk but i continue to tell him that i don't care because those kind of actions won't be tolerated. the eldest sister rushes over and says that he's not giving her the bird, she filed his nails too short on those fingers and it hurt him.  i hastily apologised and make a mental note not to assume he's flipping off his sister in the future.

TIFU by seeing my son flip the bird at his sister.