Under such circumstances, REM will take place...different from
that of while you're sleeping. The eyes will move in 3 directions
concurrently & repetitively - 1st the gal's eyes, to check if
she's noticing you, 2nd the surroundings, to see if anyone else is
looking (self-concious) & lastly, of coz, when the coast is
clear, the longkang you shall check out. 
