Saltar do sofá = jump off or from the couch

Soltar do sofá = drop (stg) off while sitting/lying in the couch. It could also (colloquially) mean "Let go of the couch." Also, "to come off/loose from the couch, as a nail, a screw etc."

Other example sentences:

-- De onde veio isso? <Where did this come from?>

-- Soltou-se do sofá, acho eu. <It must have worked loose from the couch>

--Socorro! O sofá me pegou! <Help! The couch's got me!>

--Você não consegue se soltar do sofá? <Can't you shake the couch loose?>