In and Out are relative to the center of the set.

For example, on a Press In, each dancer finds the center of the set relative to themselves, then moves one dancer position forward and toward that direction. From an Eight Chain Thru position, Press In would be equivalent to Cross Trail Thru.

From Out-Facing Lines, you could have the Ends Press In, to end in a Completed DPT.

Here's two sequences:

C1-1450
Heads Cross & Turn,
Split Circulate,
Centers Pass The Ocean,
Ends Single Circle To A Wave,
Each Side Boys Trade,
Grand Swing Thru,
Recycle,
Triple Box Square Thru 3,
Ends Press In (check a Butterfly),
IY Butterfly: Vertical Tag Back To A Wave,
Boys Press Ahead,
All Finish A Ferris Wheel,
Swing & Circle 1/4,
Centers Turn Thru,
L.A.

C2-1474
Heads Star Thru & Spread,
All Finish A Percolate,
Triple Box Chase Right,
Centers Press Ahead,
IY Triple Box: Counter Rotate 1/4,
Outside 6 Press In,
Work Siamese: Scoot & Weave,
6 By 2 Acey Deucey,
1/2 Reverse Crazy Left 1/2 Tag,
Trade Circulate & Lockit,
Grand Swing Thru,
Relay The Shadow, Girls Criss Cross It,
Cross Trade & Wheel,
Promenade Home

Ceder Chest Definition of Press