Common steps and sub-activities
Fellatio

Fellatio is an oral sex act involving the use of the mouth, which is performed by a person on the penis of another person. Oral stimulation of the scrotum may also be termed fellatio, or tea bagging. Men appear to enjoy it, it is not enjoyable for women, but they do it anyway to please the man and occasionally simply to see the effect it has on men, which can be quite entertaining.
Whether there is a danger of pathogen transmission depends partly on what action preceded this action.
For example if anal sex preceded the action, then there is an almost 100% chance that the person will get the pathogens from the anus. [Unless of course you use a scrubbing brush on the penis in-between times and a little scouring powder]. If the man has urinated, you may get pathogens from any remains of urine. One might argue that this is the case with vaginal sex, but the vagina, if healthy, has the defences to deal with this.
As the penis ‘leaks’ under stimulation, even if there is no ejaculation, there is a risk of catching any pre-existing pathogens in the semen. If you actually swallow the semen [despite its high zinc content], there is more risk involved.
We aimed to study the correlation between leukocyte counts in semen and bacterial pathogens in seminal samples of infertile men, … A total of 116 patients .. were investigated using routine semen analysis … The overall prevalence of bacteriospermia in semen samples was 56.9% … The most common bacterial species detected were Chlamydia trachomatis (41.4%), Ureaplasma urealyticum (15.5%) and Mycoplasma hominis (10.3%). PMID: 18727730
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