。
Come hang out tomorrow!
Literal
Tomorrow play [purpose-に] come-いらっしゃい.
いらっしゃい is the imperative of いらっしゃる (honorific for 来る/行く/いる), but here it functions as a warm, casual invitation — the same root form behind the shop greeting いらっしゃいませ. Despite deriving from an honorific verb, the bare imperative いらっしゃい is friendly and informal, not stiff.