stepping on toes
when you like a person or with a person and your friend starts to like/ or hook up with the person you are dating.
"jimmy is totaly steppin on toes, he knows that steve likes amy."
Don't step on my toes
What someone would say at someone treading on someone else's claimed areas, cutting someone off, inhibiting someone's progress, messing up someone else's effort, giving the short end of the stick, flirting with a friends romantic interest, etc
Waitress: hey don't step on my toes, I'm trying to get a promotion. I need to bring my A game today so just stay out of my way. Okay? :)
Waiter 2: No problem, do your thing :)
Waiter 2: No problem, do your thing :)