Honest question: If you've only only been booked by one man in the last month, but 4 times, are you still a sex worker or are you wandering into sugar baby territory?
As long as you are still open to other bookings and you are not giving him a discount then yes you are still a sex worker.
Yea its not mutually exclusive, a sugar baby is a type of sex worker. Its like a modern version of a concubine/courtesan I suppose, to drag up some slightly icky anachronisms.
Sucking cock for money is sex work, doesn't really matter how you "window dress it" or fancy-name it.