There are two documents of interest here.
1.
FAA Guide for Aviation Medical Examiners
2. Medical application
Form 8500-8
On #2, there is a check box under exam for both Anus & GU (genitourinary) system. Going to the AME guide
ANUS
II. Examination Techniques
1. Digital Rectal Examination: This examination is performed only at the applicant's option unless indicated by specific history or physical findings.
2. If the digital rectal examination is not performed, the response to Item 39 may be based on direct observation or history.
GENITOURINARY SYSTEM
II. Examination Techniques
The Examiner should observe for discharge, inflammation, skin lesions, scars, strictures, tumors, and secondary sexual characteristics. Palpation for masses and areas of tenderness should be performed.
These guidelines are applicable to all classes of medical.
Take home points:
1) The FAA does not require a digital rectal exam
2) The FAA does require assessment of anal health by "observation or history,"
3) The FAA does require inspection & palpation (touching) of your genitals
In my experience, some AME's do this - some don't. I go back to the ones who don't

There really is little medical benefit to routine anal & GU exams.