TIFU By Joking About Getting a Handie From My Partner's Roommate

So last Saturday, I (32M) went out to lunch with a friend of mine, Jack (32M). We've known each other since college, and have the same sense of humor, so we tend to be a little loud whenever we're joking in public.

Jack asked to get lunch because he knew my partner, Naomi (29F), was out of town for a conference and I would be free. We went to lunch at a quiet diner near me.

At the start of the meal, we were chatting a bit before he said something along the lines of "I'm glad we could have some guy time while Naomi is away!"

I replied by cartoonishly looking side to side, and telling him "Yeah, it's been good! But I need to tell you something. Last night, and I don't know how to say this ...Naomi's roommate gave me a handjob."

Jack started to laugh, but before either of us could say else, I felt cold water being splashed on the back of my head. I turned around and saw a 20-something year-old woman staring daggers at me. I guess she was paying-up at a nearby table, and overheard? She had an empty glass in her hand that she had clearly picked-up at an unused table that she had splashed at me.

She shouted that I was "Trash, absolute TRASH!" before storming out. I just sat there completely in shock as Jack kept laughing.

The thing that I knew, and that Jack knew, but clearly this woman didn't know: I am Naomi's roommate. We live together, just the two of us. The joke was that I was masturbating.

Now Jack is pissing himself and won't stop calling me "Trash-Absolute-Trash" like it's a military title. I know Naomi will find it hilarious too, but I'm worried I'm going to run into this pissed-off woman again at or near the diner! There is now someone, who might be living in my neighborhood, that I can run into at any point who hates me, all because of a dumb joke!

TL;DR: I made a joke implying I was cheating on my partner with her roommate, with the joke being that I am, in fact, her roommate.