"to make oneself cozy," 1857, back-formation from the British spelling of cozy. Related: Cosed; cosing.
Entries linking to cose
cozy adj.
"snug, comfortable, warm," 1709, colsie, originally Scottish dialect, perhaps of Scandinavian origin (compare Norwegian kose seg "be cozy"). In Britain, usually cosy. Related: Cozily; coziness. As a noun, "padded covering for a teapot to keep the heat in," 1863.