Regression

[Sarah]

The act of passing back or returning; retrogression;retrogradation. Sir T. Browne. Edge of regression (of a surface)(Geom.), the line along which a surface turns back upon itself; --called also a cuspidal edge.-- Regression point (Geom.), a cusp.

[Sarah]

A stress-related defense mechanism. Involves reverting to immature behavior when presented with a stressful situation or hurtful information.

[Sarah]

Roleplay in some way pertaining to age. Sometimes this is infantilism, which is adults acting as babies. There are all ages.. this can also include schoolgirl or schoolboy with headmaster or headmistress, and every conceivable age in between.