In addition to the Send to and Assign fields - which can have any email address added to them - there is a “Share” function that lets you share posts after the fact.
On web just click the little wrench icon; on mobile click into the post and click the menu on the top right.
From either, click “Share post.” Sharing in this manner takes the post out of Fieldlens. It will get emailed to the people you specify. Any replies to the email will go to YOUR email - rather than back into Fieldlens.