Why didn't he just use Super-Hypnotism to make her think that she'd just gotten a kiss that blew her socks off? One of those extra-special, one-each-ten-years-was-enough-another-just-might-kill-me-type kisses. (And yes, he did have 'Super-Hypnotism'. It was in a Golden Age story - he 'focuses his eyes hypnotically' at Lois which instantly renders her unconscious, thereby allowing him to change out of his Kent duds.)