Sleepers are effectively onesies that babies wear. Any diapers which are worn when a sleeper is put on cannot be removed until the sleeper is. You can put on a sleeper if you want, but getting it off will be much more difficult. You can rip them apart, unclassified the buckles, or damage it enough to break free. A list of sleepers is provided below.
This one weighs more, is tougher, but also softens falls.
Any wings you might have cannot be used.
This releases powder when damaged. Applies a dose of Babying Powder if touched.
This one feels so comfortable. You don't want to take it off. Attempts to remove might not work.
Extra padded, thick, and pink. You can't walk normally, and you can't hold anything. Only found in Sissy Route.
There are sleepers based on animals, called costumes sleepers, which can have different effects put together if specified.