It seems like you might be referring to a "sirth bath," but it's likely that you meant "sith bath," "sirth bath," or perhaps "sitz bath." A sitz bath is a warm water bath that is used to soothe the perineal area (the area between the anus and the genitals). It can be helpful after childbirth, surgery, or during certain medical conditions.
If you were referring to something else, please provide more context or clarify, and I'd be happy to help!