Frustrating Fajitas

Okay, so sometimes we'll try just about anything to get The Boy to eat. (He's the good sleeper, whereas Q fights sleep relentlessly; she eats, he stalls and avoids food.) My wife is especially good at coming up with ways to get him to take bites.

Recently, though, her strategy came back at her. We were having chicken fajitas, and though he really likes them, he started off very slowly (as usual) on his. He's a neat eater, however slow, and my wife saw an opening:

Mama: My fajita is all messy. Can you show me how you eat yours without spilling?
The Boy picks up his fajita and takes a big, proud bite without spilling even a sliver of onion.
Mama: That's great. Mine keeps spilling all over. Can you show me again?
The Boy again takes a clean bite, adding a little flourish as he puts it down.
Mama: I don't know how you do it. Look at my plate. Show me again how you do it without your fajita falling apart.
The Boy: Mama, I don't think that we should have fajitas anymore. They make you too frustrated.