Timeshare

You press the 'stop' button on your stopwatch, causing time for you to slow, while speeding it up for a willing creature within range.

As part of casting this spell, you may choose to incorporate your bonus action and movement into this spell, as long as you haven't used them this turn, and as long as the receiving creature could use them. After this spell is successfully cast, you forfeit the chosen options on your current turn, and one creature of your choice that you can see within range gains an additional turn this round, taking place immediately after your own. During this turn, the target can take an action as usual, but cannot use a potential bonus action or their movement unless the caster sacrificed their own as part of the spell. This does not affect the target's initiative, and it acts as normal on successive turns. 

At the end of each of your subsequent turns for the duration you may make the same choice, targeting either the same creature or a different willing one within range (no action required). However, in addition to being able to choose whether or not to give your bonus action and movement, you may choose whether or not you also want to give your action. If you choose not to, the creature cannot take an action. If you do not include at least one of those three, the spell ends.

This spell also ends if it is cast again on either of the connected creatures.