Did you have a great time last night? Did the top really give you a good scene? Did they help you feel really good? Did you enjoy yourself?
Then drop them a little note the next day.
Many tops (including myself) will tell a bottom that if they have any trouble/concern/drop to let them know. We generally like to be there and help.
But correspondingly, if you had a good time, letting the top know makes me feel really good. It lets us know you're alright, it can help alleviate any lingering doubts, and it's generally a great little ego boost.
If you do this, the top is going to be more likely to want to play with you again too!
A short note can go a long way!