Not so much the butt but the lower back, and one does also lick his feet.
You said “base of tail”, so I thought anal area. Tara sometimes goes after her underside base of tail.
My dog this year has progressed to getting spinal itchiness. Originally, it was because of a massive staph infection (the real danger of allergies). Right now it’s alot of dandruff. We go to the Derm this week so we’ll see if he thinks she’s infected again (I think so - too many circular red sores popping up everywhere to just be simple irritations).
Let’s just say Tara is a mess and gets itchy everywhere, even if it’s not visible! She is probably the extreme of bad allergies.
Does he lick inside his paw pads? Or just on the top? They can itch anywhere on the foot, but the worst shows up in the pads.