Even with an aftercare kit, it’s likely a bottom/sub/slave will suffer from sub drop occasionally. This can happen even if they don’t get reach sub space and it’s very hard to anticipate what will cause it. The aftercare kit is good to have anytime after a play session, even if they don’t drop. Sub space can make the euphoria so strong, that a sub is unable to speak or feel intense damaging pain. The best thing to do as a Dom is to watch them carefully. It also helps to know your sub. Some need to be cuddled and cared for and others want to be left alone. For those subs, I would still watch them from a distance and make sure they are warm and safe. Also make sure they drink some water, as they are likely to be dehydrated.
What you include in an aftercare kit is highly personal, such as a sub who identifies as a little might want a stuffed animal, candy or cookies, Disney movie and a blanket.
For me, these are the things I have in my kit:
Hot shower with lavender or juniper shower gel
Soft robe, nightgown or blanket
Comfort food (juice, tea, toast, mac and cheese, ice cream, chocolate)
Arnica gel (great for bruises and cuts that you don’t)
Relaxing soothing music
Hand cream (I have three kinds I love; lavender, grapefruit and lemon)
Journal and pen
Coloring book and crayons
Crying, if needed