An escort is usually a sex worker who
does not make her profession explicit in contrast with a street walking
prostitute and does not work within institutional framework (e.g. at a brothel),
although it is not excluded that she works through an escort agency. The client
has to reserve a date in advance by telephone agreement, so this is why they
are sometimes called 'call girl'. Escorts normally advertise their sexual
services in magazines and on internet sites however escort agencies and less
often pimps may also play a role in advertising sexual services.