ただしイケメンに限る
Tadashiikemennikagiru
ただしいけめんにかぎる
Born on 2ch forums, this set phrase means 'that's only acceptable if you're good-looking.' Often shortened to 'tada-ike.' Used as self-deprecating humor about how attractive people get away with romantic gestures that would be creepy from anyone else. Applied beyond dating — 'X is only okay if you're hot' — to express the harsh reality of looks-based double standards. A defining expression of internet non-mote (unpopular) culture.
Examples
壁ドンとか少女漫画の世界でしょ。ただしイケメンに限る
Kabedon? That only works in shoujo manga. But only if you're hot.
Chatting with friends about romance
駅で声かけて連絡先もらえるとか、ただしイケメンに限るだろ
Approaching someone at a station and getting their number? But only if you're hot.
Forum post
不意打ちのハグが可愛い？ただしイケメンに限る
"Surprise hugs are cute"? But only if you're hot.
ただイケの法則、世の中の真理だわ
The tada-ike rule — it's just how the world works.