The DDS bit is just Weinersmith accidentally using the wrong degree. This is one of the older comics where the bonus panels were drawn by him going back to old comics after over a decade, so he’s just drawing himself as confused as to his previous mistake.

The actual panel isn’t that deep I think. The guy is dumb and doesn’t realize that offering to pay for her facelift implies his wife is unattractive and needs a facelift.