Superman would never kiss Lex Luthor, would he? (Well, depends who you ask.) But Supergirl? Totally:
Okay look, it's when Lex was in a younger, more brawny, more hairy clone body acting like he was his own illegitimate son. And okay, it's not actually Kara, but Matrix, the artificial Lana Lang created by a heroic Lex Luthor from Superboy's Pocket Dimension. Fine. You got me. Just wanted to get this dating series out of the Silver Age. Sheesh.