Fuck how you tell him
Tell your boy how good it was but that to make it better you have to control his orgasm.
Wait for sunday night. Then tell him you have a test to make. Tell him to get naked and cum as fast as he can and be sure to remember the time he has made. then tell him "this is why I don't have a full orgasm". Explain to him he has to give up control on his ejaculation to you. In order to do that tell him "you have to do a small program. It is gonna be hard but the outcome is wonderful"
The program is called "cum in 60 seconds when I tell you"
the duration is four weeks.
First week be sure he is hard then take a clock and wank him very fast till he cums. Do that every day. If he cums, confort him about the good progress. When he doesn't tell him he is not making enough efforts. It has to be done every two days.
Second week, same thing but he masturbates himself while watching you encouraging him with the lingerie you bought. every two days.
Third week, same thing but just ignore him. and make a countdown every two seconds from 30. every two days.
Forth week, "this is the big test honey". Your boy has to cum in 60 seconds every day while watching you clothed. Do that during five days. If he has failed to cum only one day, try it again and again if necessary.
After he finally makes it, you can have the big bonus. Wear his forth favorite lingerie and do his forth favourite sexual act.