two-timing (slang)

literally: 'stepping on two ships with one foot', to date two people at the same time; two-timing

to ride a bike

down-to-earth / good foundation

on the spot (timing; spoken)

to describe something that is nowhere to be found even after painstakingly exhausting all of one's energy and effort to look for it

a stepping stone (a metaphor for someone who is being used as a stepping stone by others to reach their goals)

to be a player in relationships, having many lovers at the same time [written and colloquial]

errant; to go down the wrong path; to make a mistake [colloquial]

to set foot on

outing in spring

solidly

trample

set foot

mark time

down-to-earth

pedal

march with big steps