Hmm, “sǎng zí tòng” appears to be the same as “hóu lóng tòng” (I always remember the latter one by thinking it means “have long tongue” as a symptom of something being wrong with my tonsils etc. Hi, hi!)
Generally speaking, “tòng” seems to indicate sickness as in “wèi tòng”. So, to remember that one, think of a patient at the doctor’s having to show their tongue while being examined. :-)