Stan sent this in and provided a summation of the storyline that led up to it.
Stan’s summary: “Got a head-scratcher here… Peanuts had a running storyline of Snoopy getting obsessed with the idea of a big bad wolf coming to blow his doghouse down. To calm him, Lucy draws some lines on the doghouse to make it look like it’s made of bricks to thwart potential lupine attacks. Then this strip comes along. I haven’t got a clue what Snoopy is going on about.”
Mitch’s response: “Thanks for explaining the backstory! That explains what has happened that annoys him so much: the rain has erased the brick design. I guess his verbal expression of annoyance is meant to resemble the sort of cute-colorful countryisms at one time associated with Dan Rather, or some TV old lady who said something about grits. Only, he’s not a country-and-western dog , so he comes up with some other annoying thing to compare it with. But he is just giving it as a comic comparison, not saying anything actually about heating pads. Nor any connection to the brick doghouse story, either.”
But is that funny? Does it require some substantial point of connection?
For your context & amusement, here are some of the strips establishing that story: