A Moe defensive deck will be attack by Babe deck (Moes are strong against Sexys and weak against Babe).
When your card is strong against another it SED (seduction) will be threefold, so your card only need a third of its adversary SED to be able to win.

That's why I want to use 2 Sexy, even if I have 3 card that will be likely to lose the 2 Sexy will likely win + the bonus card from friends it mean I can win if I'm lucky xD

The base of a trap deck is to lure people with 3 card of a attribute (you need 3 to get an attribute on your "profile"), and then use 2 card of the attribute which will be strong against the one that the attacker will be most likely to have.

The reason why you want to be attacked is because you lose nothing if you actually lose the defensive fight.

EDIT : As far as I know, before fighting you can only see your adversary general attribute (Moe, Sexy, Babe or none) and not the actual cards.