There has been lots of talk about erotic attitudes and their roles in intertype relations, so I figured I'd do some speculating about their origins in Model A.
We all know that the need of one type for another is driven by the inadequacey of each type to comfortably meet all of the expectations placed on him/her. That's pretty basic: Ne needs Si, Se needs Ni. What most people don't look at is how the insecure functions of each pair play into erotic compatibility.
Perhaps the other, darker origin of intertype relations is based insecurity that originates in the insecure mental track irrational function and is expressed in the roles played out by partners in erotic attitudes.
Paranoid Se: "Sometimes it feels like the world is working against me; I never have everything I need to accomplish my goals. I just want one person who will always help me, even when it feels like everyone else is working against me."
Basic desire: To be supported
Paranoid Ni: "I feel like I don't have any purpose in the world; I wander through life without really being sure of what I'm going to do with myself. I just want one person to need me so I know that, if all else fails, I have something to live for."
Basic desire: To be needed
Paranoid Ne: "I'm never sure of what I'm really capable of. I'm always ready for a challenge, but I'm never really sure whether or not I have what it takes. I need a person who can test me, and help me feel reassured about my abilities."
Basic desire: To be evaluated
Paranoid Si: "I often feel like nobody values or needs me. I want someone who is willing to strive to attain me, so that I know that I'm worth fighting for."
Basic desire: To be desired