C.A.
My daughter has been doing this to me too and it makes me crazy. BUT! My strategy has been to clean it up once a day and when she does this with her food.
I have been trying to not make a big deal out of it as well in case it's a plea for attention. That seems to be the most effective thing I have managed to do during this phase with her. I give her a couple of tries and if she does it to me twice in a row then I put her food away and we go do something else for a while. But I try not to even show a reaction and I do not clean it up when she's watching me.
This has been going on for about 3 weeks but seems to be slowing down a lot-we have gone a couple of days now where I haven't seen her do this so we might be done. I know this doesn't help right NOW, but it's temporary and eventually he will lose interest in this maddening activity.
A while back, my daughter would secrete yogurt (there's really no other way to explain this) after she would take a bite of it...we had to stop having yogurt for a while and now when I give it to her she doesn't do that to me anymore.