to know if you have enough mana for the following spell turn on option " show mana cost" in options, then you can see how muchmana do you need for just one or for two spells.
Was searching for it myself, I think it's this one "Onegai Muscle"' aka "Dumbbell Nan Kilo Moteru" . Link : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-FIRcjetBKFY.html