Sometimes, if your badminton grip starts to slip off the racket during a game, you can fix it on the fly. If not, there are a few things you can do to fix it quickly.
Work a bit of rawhide or leather cord through the hole in the grip
Twist the cord a few times to create some density in the area around the hole
Pull the remaining cord through the shaft until you reach the density you created in the shaft
Tie a knot to secure it and you’re done
If you don’t have any cords, you can use tape to secure the grip in place. Just wrap the tape around the grip and over the ridge at the top of the racket shaft.