to be in the kind of situation where one enjoys oneself and performs at one's best; to be at one's best, to be in one's element
çekim: geçmiş var i sitt esse
köken: Literally, "to be in one's esse (only used in this expression)," a partial calque of German in seinem Esse sein, from German Esse (perhaps in the sense of "inner nature" – compare väsen), from Latin esse.
Nisse älskar att laga mat och är i sitt esse vid grillen på grillfester
Borrowed from Danish være i sit es, from German. "Ess" is from Latin esse (“state, condition”). Ásgeir Blöndal suggests the phrase may be influenced by French être à son aise, cognate with English at ease.