Playbooks

Smash Post out of Shotgun Doubles gives you a true Cover 2 beater on the left side and a corner/flat combo on the right. To the left, the outside receiver runs a corner route (yellow) up the sideline while the inside slot receiver sits underneath on a hitch (yellow), forming the classic smash concept that stretches the flat-to-deep-outside defender vertically. To the right, the outside receiver breaks on a deep post (red) that stems away from the safety while the underneath receiver runs a shallow drag/flat route (yellow), pulling the shorter zone defenders horizontally. The primary read starts with the post on the backside since it attacks the middle of the field against single high or Cover 2 shells, then progresses to the smash combo on the boundary if the post window closes.
Watch the free safety at the snap: if he stays deep middle and does not widen toward the post side, the post will be covered and you should work the smash combo instead. Key the flat defender on the smash side: if he squats on the hitch route, throw the corner route behind him for the explosive gain. Diagnose linebacker depth before the snap, since shallow linebackers can undercut the post route and rob the crossing window if the quarterback stares it down too long. Look for a user controlled defender lurking in the middle of the field, as this play is vulnerable to a rat in the hole sitting on the post read. Cover 2 and Cover 4 shells with soft corner leverage are the easiest to exploit, while Cover 3 sky or a robber concept with a deep half safety cheating over the top will shut down both the post and the corner route.
Pre-snap, identify whether the safeties are showing two high or rotating to one high, since the post route only has a throwing window against Cover 2 or Cover 4 shells where the safety has to widen for the corner route.
If you see Cover 3 or a single high safety sitting in the middle of the field, hot route the post into a skinny post or dig instead, or check down to the smash combo on the opposite hash.
Use play action from under center concepts or run this after establishing inside zone to freeze linebackers and open up the post window against teams keying run.
This play pairs well with Flanker Dig and Deep In from the same set since all three attack different levels and force defenders to declare their leverage before you pick the right one at the line.
Best called on second or third and medium when defenses are more likely to sit in split safety shells trying to prevent the deep ball, since that is exactly when the post route has room to work.