Forward Lock

Notes
Alex Moore and Guy Howard note in their respective techniques that the lock step action is the same forwards and backwards for both the Man and the Lady. The term Forward Lock is choreographic shorthand for the combination of a Man's forward locking action with a Lady's backward locking action.

The Forward Lock as part of other figures
Steps 2-4 of the Forward Lock are included in the Tipple Chassé to Right and the V6. Additionally, the Man's forward locking action is featured in the Fishtail, the Four Quick Run, the Six Quick Run, and the Rumba Cross. 

Checked Forward Lock
The Ballroom Technique notes that a Forward Lock may be checked on the
5th Step (S)(Man's RF OP). The Man continues back on LF (S)(Lady RF fwd
OP), into a Four Quick Run, a V6, or a Six Quick Run.

2-4 Forward Lock
Several figures, most notably the Tipple Chassé to Right, the Tipsy to Right, and Steps 1-5 of the Natural Turn already include the first step of the
Forward Lock. In this case, the Forward Lock will begin with the Man's LF diagonally forward (Lady's RF back).
 
Bridge Step
Both the Ballroom Technique and The Quickstep and Basic Principles permit a Bridge Step (Man's RF Forward OP) into the following exit combinations:
-Any Reverse Figure (IDTA)
-Quick Open Reverse (ISTD)
-Tipsy to Left (ISTD)