Can you activate a mana ability during the resolution of another spell?

Mana abilities are a special category of abilities that do not use the stack (CR 605.3a). Because they resolve immediately and cannot be responded to, the game specifically allows them to be activated at times when players would not normally receive priority — including during the resolution of another spell or ability.

CR 605.3b states that a player may activate a mana ability whenever they have priority, whenever a spell or ability instructs them to pay mana, and whenever a rule requires them to pay mana. This covers situations like paying an additional cost mid-resolution or satisfying a "pay X mana" instruction inside a resolving spell's effect.

Crucially, mana abilities themselves do NOT go on the stack (CR 605.3a), so there is no window for anyone to respond to them. They simply resolve immediately, producing mana, and then the resolution of the original spell continues from where it left off.

Example: Your opponent casts Tempt with Vengeance and you decide to accept the offer, creating tokens. The spell's resolution instructs you to put token creatures onto the battlefield, but say you need to tap a land for mana to pay a triggered ability's cost that fires at the same time — you can activate your Forest's mana ability right there during resolution to produce that green mana without issue.

Note that non-mana activated abilities still require priority and cannot be activated mid-resolution of another spell. Only mana abilities receive this special permission (CR 605.3b).