YOU might use it, but some of us may resent the WE. I presume you understand the clinic bit. Clap is a slang word for gonorrhoea which at one time was one of the commonest forms of sexually transmitted diseases in the UK. The word clap is derived from the French word "clapoir" which means venereal sore, which is further derived from the French word clapier which is a brothel.
For information they are now known as GUM clinics which stands for Genito-Urinary Medicine. For anyone who wants advice or to know where their nearest clinic is there's an excellent web site at :---
http://www.homehealth-uk.com/medical/gumclinics.ht m
. The site is well worth a look because you never know when you might need it.