on demand
When needed or desired. Often hyphenated. It can be difficult to adjust to a baby's need to feed on demand. Cable television is being replaced in many homes by on-demand video services.
on demand
When needed or asked for, as in She's always ready to sing on demand, or Nowadays infants are generally fed on demand. This usage is a broadening of this phrase's meaning in finance, that is, "payable on being requested or presented," as in This note is payable on demand. [Late 1600s]
on deˈmand
done or happening whenever somebody asks: Feed the baby on demand. on demand
1. When presented for payment: a note payable on demand.
2. When needed or asked for: fed the baby on demand.