noun
horny drunkard
Slang, derogatory term for a person who becomes sexually aggressive or lecherous when drunk. The suffix 上戸 refers to a type of drinker.
あいつはエロ上戸で、酔うとすぐに手を出してくる。
That guy is a horny drunkard; as soon as he gets drunk, he starts getting handsy.
Compound of エロ (erotic) and 上戸 (じょうご, a suffix for types of drinkers). The exact origin is uncertain, but it follows the pattern of other 〜上戸 words describing behavior under the influence of alcohol.