Cuming with the top of my dick stroked during a LDK

Yes the best part is underneath the Dick especially near the head.. of course But... Recent LDK I've been popping with then rubbing their ass all over my Dick with my legs spread wide open and sick down I can feel her ass stroke the full length of the top side of my dick... it takes longer but usually after twenty-five minutes on average I'll bust and do so Hard Honestly can't explain it myself... it just feels amazing over time LMFAO