I am not assuming she made a plain offer.

i keep peanut M&Ms on me w the specific purpose of offering the guy one when i see him, and offering them again whenever i can tell he feels vulnerable.

I admit my inferences are predicated on the context that she is applying dog training but it is entirely core to the discussion. Her quote says not "some [M&Ms]", but "one". She's doling them a singlular M&M at specific instances. Again like trainers do when they're priming a reward for an animal after they perform the right action. And her self-defense is based on the idea that humans aren't that different from dogs and the boyfriend isn't aware of her actions, instead of anything normal like "he said he's glad I'm helping him" or "he's shown he's appreciative that I'm helping distract him from stress".

I'm getting the picture she's more doing "hey , here's an M&M" when she's training then anything resembling a clear mention of a helpful motive.