I was never in the service industry but dated / had friends who were, and I was told that the term “Canadian” was substituted for “black people.”
instead of “I love you” I say “how 'bout them Lions?”
About once a month or so our good friend Enoch comes to stay for a few days. Named after Enoch Powell the uk politician. He was most (in)famous for a particular speech he gave on immigration. It was known as ‘the rivers of blood’ speech. I usually have to explain it to non uk people who then either groan or throw up.
I haven’t smoked for a year now, but on my lunch-break in the past, I used to “check the weather.” I was smoking, no matter the weather.
Oh, I see. 
It’s like getting a visit from Aunt Flo?
Set up the chamber - Light a fart when others can’t easily leave, so they must endure the torturous smell. “Dammit Joe, I could barely watch the end of the movie; you set up a serious chamber back there!”
Call in to a meeting - Go to the bathroom, usually for number two (confusing to use at work). “Can we finish this later? I’ve gotta call in to a meeting.” “Oh, is Susan attending?” “I hope not.”
Amp up the man factor - Skipping a shave. “Nice, looks like someone’s amping up the man factor!” “Yeah, I woke up late this morning.”
Max out the man factor, or Lumberjack Mode - Reaching a critical mass of hair after not shaving for quite a while. “Damn, Seth just hit Lumberjack Mode. I don’t even recognize him.”
Smoke it - Finish a game or book from beginning to end in one sitting. “Back when I was a kid, I smoked the first three Harry Potters, one after the other.”
Euphemisms I’ve developed from my wife’s point of view:
“I got rid of some poison” = I took a crap
“Don’t get any cold air on your stomach” = Stop launching stinky farts at me, you disgusting pig
Lately I’ve been saying, “Let’s see if they found that airplane yet” to mean, “I’m turning on the TV”.
The sound of the shower going on scares my dog. Any discussion of showering gets her whining in anticipation.
The kids now take “walks in the rain” instead.
Back when I had roommates, if you knocked on someone’s bedroom door and they said “Don’t come in. There’s a bee in here” it meant they were masturbating.
Over time it became used for any “I’m busy” situation. Either that or my roommates masturbated a lot.
I’m totally gonna steal that one.
Like a surprising number of posters, we have a few for the dog. He quickly learns the words that suggest, even slightly, that he might be getting a walk soon so we cycle through a few rephrasings: “we’re taking a stroll” or " I’m doing the thing with the thing" or “taking you know who.”
My wife and I have a texting shorthand, since her phone is often in the hands of our kids. We each enjoy a little private solo sexyfuntimes during the day, and typically the urge hits when I’m at work. So when one of us has taken matters into our own hands in the bathroom, we’ll text the other a smileyface.
When we’re home and I need to let her know that I’m going to the bathroom for more digestive-related activities and it might be a while before I’m done, I just mention that I have to catch up on some reading.
And when I used to work in theater, when one of us would pass the slow times smoking a little weed, we’d say we weren’t in the office because we were doing a “dimmer check”.
Ashtray- a trashy person (Ex. Did you see the ashtray next to the door?) Also phoentically identical to the Pig Latin way you would say trash.
When I worked at Space Camp “going for an OMS burn” meant taking a smoke break. Another counsellor used “John Glenn” as a curse word.
“Barking spiders” for farts.
“Going to the library” meaning using the toilet (there’s lots of reading material there)
That certainly puts Mrs. Murphy’s Chowder in a whole new light…
Scooping poop for us is “picking mushrooms” probably because the stuff starts to sprout if the weather is right.
One of the dogs gets pills daily, and she happily gobbles them down when rolled in a piece of sandwich cheese, so she gets “magic cheese”
Shark Week = period
“Wanna go to the movies with us?” “Nah, it’s Shark Week. I’ma stay in, eat ice cream, and be moody.”
The teenagers I know refer to that special time of the month as “a visit (or a gift) from Mother Nature” or “Shark Week.” The Mother Nature thing is a reference to a feminine product commercial in which Mother Nature would appear to young women carrying a gift wrapped in red paper.
I used to know a guy who would say, upon going to the bathroom, “I’m gonna go send a package to Long Beach.” Long Beach is where the local water treatment/sewage plant is.
Years ago, my little rat terrier figured out most of the words that pertained to going for a walk. As soon as she THOUGHT we were talking about going for a walk, she’d start jumping high into the air repeatedly.
She was usually right, too.