The thrill for him? Of hungrily stroking whilst she's laid out moaning and bucking and clawing as another man pushes deep inside her and she just cannot contain her excitement? Of being allowed to worship her freshly fucked pussy with his tongue, whilst it's still swollen and hot and musky from mixing her untameable desire with that if her bull? Of having her suck and stroke his cock, describing to him how much she loved to get used by this talented intruder, as she felives the experience with her fingers and he cakes her body with cum as they both orgasm, together?