お昼、一緒にどう? — Lunch — wanna grab some together? (Workplace · Socializing, Casual — to friend, JLPT N5)

Gesture & etiquette

Casual approach at the colleague's desk. Light hand wave or shoulder-tap if close, friendly smile, eye contact. If they hesitate, give them an out — 'もし忙しかったら、また今度で大丈夫だよ'. Don't push.

Casual lunch invitation between peers. 'どう?' is the most casual question-ending — implies 'how about it?' Use only with people you have informal relationships with. For superiors, use 'よろしければご一緒しませんか' (if it is okay, would you join me?). Group lunches build the お昼会 culture in many Japanese workplaces.