Some people use the top part of a plastic soft drink container, placing it over the Tubastrea and feeding thru the hole.
I used to just remove the coral and place it in a tupperware bowl full of tank water. Personally, I felt this gave me better control of the feeding and less waste in the tank.
Either way you can use a turkey baster and swirl the food around until as many polyps are fed as possible. People have had good results using both of these methods.
Good luck!
