Back to Gently. I found my unabridged dictionary and looked up "kittle."

verb: 1. to tickle 2. to perplex

adjective: runs the gamut from ticklish to dangerous. Mostly seems to mean "hard to get along with." Apparently the phrase "kittle cattle" was common. I like that.

"Kittle" comes from the Middle English and is labelled Scottish and dialect English.
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What about the jenny (car part) and the p.p.?