ASUKA:“If I were to warm up just my breasts,
do you think they'd grow a little bigger?”
SHINJI:“I wouldn't know anything about that!”
Zusuchan: This is pretty clearly Asuka flirting with Shinji-even if you want to argue the reasons are, well, somewhat different than "I like him", it certainly shows she's not uninterested enough to not do something like this. Shinji's reaction is, of course, complete embarrassment and nothing else.