So. I guess you didn't like the Duluth Trading idea. I was thinking, if you wore those pants. It is possible, he could mistake your knee fur a fire hydrant. ... :B
May be try one of these 1/2 zip pants.
These are Cabela's, but there other brands of 1/2 Zip Pants!Shorts while at home, and he's licking your knee. Then when you decide to go out, wipe / clean your knee, zip the bottoms on, and "wah-lah". Nice Clean Long Pants / Slacks!
Pops, ... I mean, ... Anonymous
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PS Anonymous Jr. says, "Survivorman" swears by these pants. He used them in his African Plains Episode. When it got hot, he zipped the bottoms off. Then when it got cold, he zipped'um right back on.
Not the same as a dog licking his knee, but I think yous gots the idea. ...