Similar to friends with emotional benefits. More commonly a boyfriend/girlfriend without the rewards. Typically a guy/girl friend used for the emotional benefit out of a relationship, while the physical benefit is being taken care of by another guy/girl one has no emotional connection to.
Nick: I'm your emotional fluffer; I'm there whenever you need a guy. You want a cup of tea, I'll make it, you lose your phone, I'll call it.
Jess: You're my friend! That's what friends do.
Nick: I'm your boyfriend without the rewards.