No. While it may be theoretically possible to get HIV from a rim job (i.e. oral-anal sex or eating ass), most health experts believe this is safe sex in terms of HIV transmission.  There have been no cases reported of HIV transmission through oral-anal sex. Oral-anal sex can, however, transmit shigella, amoeba, giardia, hepatitis A and maybe even syphilis and gonorrhea. There are vaccinations available to prevent you from being infected with hepatitis A and B. Regular STI check-ups are also recommended as a good way to stay healthy.