I'm FtM btw
"Grandma, I have decided that instead of being a stupid meat hole for men to lust over, I'm going to cut off my tits and rub hormones on my clit to try and look more like a short man with a high voice. Don't worry, I'm sure it's a good idea, I spent a lot of time on the internet."
My own submission:
"Hey gram-gram, you know when you were little and wanted to be a dinosaur? Well, guess what...when I was little, I was a girl and now I want to be the man I've always thought I was and am. I'm FtM."
"Yo, Grams, from now on I'm a dude and if you have a problem with that you can suck my dick. Because I'm getting one. And it's going to 12 inches long to compensate for my small dick syndrome"
approach her and say
'hey im tranny' then go become this and make out with me
I've overhead two (cis) girls talking about something similar here only about tests. Their plan was to tell their dads they were dating black men and then say they're joking and that they failed their tests. The idea being that dads would be relieved enough not to be bothered by test scores.