With the way your plant is currently potted, it sounds like it will be very difficult to know when and how much to water, which will surely end up stressing out both you and the plant. Really, it would be best to repot it entirely. Try carefully removing the rocks to see if there’s any way you could get the plant out of the pot. If it’s cemented to the bottom of the pot, perhaps you could carefully break the pot apart (assuming it’s terracotta). Be careful not to snap the stem of the plant in the process. If you can manage to get the plant out, replant it with a succulent potting mix in a pot with a drainage hole and follow the care instructions outlined above.
If there’s absolutely no way to get the plant out, you could create a makeshift dip-stick to tell you when there’s no water left in the bottom of the pot. Assuming the rocks are fairly loose, take a straw and feed it down to the bottom of the pot, leaving a bit sticking up from the surface. To check the water level, take a piece of string and feed it through the straw to the bottom of the pot. If the string comes out bone-dry, it’s time to water again. Be careful not to water too much at once, as you don’t want the base of the plant to sit in water.
With the way your plant is currently potted, it sounds like it will be very difficult to know when and how much to water, which will surely end up stressing out both you and the plant. Really, it would be best to repot it entirely. Try carefully removing the rocks to see if there’s any way you could get the plant out of the pot. If it’s cemented to the bottom of the pot, perhaps you could carefully break the pot apart (assuming it’s terracotta). Be careful not to snap the stem of the plant in the process. If you can manage to get the plant out, replant it with a succulent potting mix in a pot with a drainage hole and follow the care instructions outlined above.
If there’s absolutely no way to get the plant out, you could create a makeshift dip-stick to tell you when there’s no water left in the bottom of the pot. Assuming the rocks are fairly loose, take a straw and feed it down to the bottom of the pot, leaving a bit sticking up from the surface. To check the water level, take a piece of string and feed it through the straw to the bottom of the pot. If the string comes out bone-dry, it’s time to water again. Be careful not to water too much at once, as you don’t want the base of the plant to sit in water.