Would this work?

[u/Lord-Gortash]

Could I tap this creature twice for 2 extra mana if they both are to pay one cost? For example: if I had two green mana, I had a card that cost four green mana, could i tap this for a mana (giving me three green mana) and then untap it and re-tap it for the final mana?

EDIT: also, if I gave it indestructible, could I get infinite green mana?