Trending @Infosys; How to deny working for two projects together to manager

Just remember how your crush rejected you without any hesitation when you expressed your feelings for him/her. Do the same.
In short, be bold and straight forward, deny politely, if they force, drop them a mail to pay you accordingly. Don't hesitate at all.

How to get in two projects? Like my current project is on Autopilot most of the time.

Two projects for one account is always possible if your allocation total adds up to 100%