Fumi

When the ship is between a younger character and their guardian figure who is in love with them but is afraid of breaking their trust and making them feel unsafe so they are constantly battling with their own morals and having to decide whether they should destroy the safe figure they provide in favor of their own lust or keep up their facade of normalcy to keep the one they love safe while suffering in silence

Light wanting to kiss L (it's a bluff). L agrees (calling the bluff). Light having to proceed or else he'd look stupid for bluffing (he fucking hates it and wants to kill L so bad). L reciprocates and makes it intense to establish dominance and corner Kira (mentally increasing suspicion meter by 15%). To the task force it just looks like they're making out heavily. No one but them knows that Light is two seconds away from barfing because of the taste of sugar and L is willing to lengthen the kiss to proposition Kira further because refusing would make it look weird for Light (Light is indeed red in anger).