Looking for a specific Steve scene

[caedesdeo]

I'm looking for an older fic that has a scene in it where Steve demonstrates that he can tie a knot in a cherry stem using his tongue, I think showing Tony and someone else. They ask where he learnt how to do it and he says a woman (possibly a model or someone at a party?) showed him she could and he asked her to teach him how. Tony and whoever comment to each other that Steve had no idea she was trying to flirt with him.

Anyone recognise this scene?

Edit: Never mind, found it: on tumblr