Literal translation
to go softly-softly
Meaning
to go slowly, gently
Explanation
To go slowly, gently, at a measured pace. The adverb plan, a false twin of the Italian piano, is almost always used in its doubled form, plan-plan, a common intensifying device in Provençal that also adds a touch of comic effect. Calling someone plan-plan is generally more a criticism than a compliment, Provence favoring lively people and things that move fast.