The eyes emoji is most often used to mean 'I am watching this carefully', 'I see what's happening', or 'something interesting is going on here'. Posted under a friend's flirty photo it might mean 'I see you'; posted under gossip or news, 'I'm paying attention'. It can also indicate suspicion or curiosity. It carries no sexual or coded meaning in standard youth use. If your teen sprinkles eyes emojis into messages they are usually signalling attention or playful nosiness, not anything to worry about.