What is it and how do you get it?
NSP, or non-specific proctitis, is an infection similar to NSU except that it is found in the arse rather than in the urethra. NSP is 'non-specific' because it is often impossible to identify the exact cause. NSP is mainly caused by getting fucked without a condom or by being fisted.

How do you prevent it?
Using condoms for fucking can prevent most cases of NSP.

How do you know you've got it?

It is accompanied by an off-white discharge from your arse, which may cause slight itching or discomfort.
A sexual health clinic can test you for signs of NSP, and it may be diagnosed if you have symptoms but the results of swabs from the arse cannot confirm the cause.

How do you treat it?

NSP, like NSU, can be successfully cured by antibiotics.

Which sexual partners should I inform if I've been diagnosed with NSU?
If you have symptoms, you should inform anyone you've had sex with up to four weeks before the symptoms started. If you don't have any symptoms, you should inform anyone you've had sex with in the last six months, or your last sexual partner if it was longer than six months.