It boggles my mind thinking about how good Eliot is at reading body language. I mean, just remembering that post about the moment in Nigerian Job where Eliot knocks Hardison's legs out of the way but steps gracefully over Parker's legs and how that was telegraphing "I'm safe to be around" to both of them in their own body languages, and there's a similar moment in The Tap-Out Job right before Eliot shows his knowledge of boxing by having Parker and Hardison spar while he coaches them:
Eliot: Let me show you something. (slapping Hardison on the shoulder) Hardison, come here.
Eliot: (guides Parker into position with a hand to the waist) Can I borrow you for a second?
I mean this is exactly the same thing. Hardison he can tussle with and frequently does to show he can pull his punches (both verbally and physically) but Parker hasn't reached play-fighting stage just yet so he's still gentle side first with her. They've obviously progressed to a level of closeness where Eliot feels comfortable guiding Parker, teaching her, and also feels comfortable that she'll go along with his demonstration, but he still asks. It's the kind of perfunctory ask where you're sure the answer is yes, but it's still an ask. It's just a beautiful little moment and I love it.