Hi
that setup look like a plastic pot inside a sealed outer pot . If you water as it is, you could well get problems because water can't drain out of the outer pot and cactus do not react well to water sitting in their base roots. You should remove the inner pot when you water. This is a major chore and as you point out can be difficult when the plant is spikey
. The long term solution is to plant in a pot with a hole already in it (such as a terracotta) or even get a tile drill bit and drill a hole yourself in your outer pot.
Other observations from me would be your plant is sitting too low in the outer pot anyway. You want the base of your plant to be level with the top of the pot. Also you plant looks to be behind blinds. This will drastically restrict the amount of light it gets (even with the blinds open) so it can't utilize any water into growth because it needs adequate light to do it. Cactus indoors need to go right up against the glass in your sunniest spot (ideally south facing) if you are in a relatively cold / dull climate like me in the UK, your soil will needs to be very fast draining or it will stay wet too long and cause problems and rot. It looks like you are watering then by splashing water down the side of the plant , This also is not ideal unless the spot is sunny and hot enough to quickly evaporate the water. You can get localized humidity . You should water at the soil level or from below unless you have very sunny conditions .
You need to be sure there is no rot at base level of the plant or it can quickly spread and kill the whole plant. If this were mine I would take it out of the outer pot an inspect the base of the plant, if it is soft or mushy at all, then it is rot and you might need to act drastically to save it. If its OK, then move it to you sunniest location and let it settle whilst you decide what to do about the other issues. You can use gloves or wrap the plant in paper to help with handling it , but you are probably going to get spiked a bit i am afraid.
Daisy asked you how you decide to water not how often you do it, its an important distinction . Please read the threads on watering, light and soil at the top of the forum as these will give you an idea on how others have had success.
There are many route to success and others may have more specific advice related to this plant as it is not one i keep.
Best of luck and let us know how you go on
Steve
