During the Credits
There is an extra scene during the credits of Blockers.
In the extra scene, Mitchell (John Cena) and his wife are shown playing the same blindfolded Marco Polo sex game that he caught the other parents playing naked. After they find each other, their daughter walks in on them and screams.
After the Credits
There is no stinger after the credits of Blockers.
Special thanks to mikekeam, Jezamiah, Divebud171, LordCrom, and GRHM for the stinger submissions!