No but you can catch sexually transmitted diseases such as HIV/AIDS. If you want to give oral sex to a man (and i stress the word want - you don't have to if you don't want to) then you can buy flavoured condoms.
Only if semen is on his fingertips.
Yes. A tired man can still produce semen. It might take more effort but as long as he can put semen into a woman's vagina, she can become pregnant.
Not with his own semen. Though if he came into contact with another man's semen (having sex with another man or even a woman who recently had sex), then the "foreign" semen could impregnate the woman.
Yes.
Felching is a sexual practice in which semen is sucked out of another person's anus. The individual sucking the semen may swallow it or pass it, mouth to mouth, to a partner. The term for the latter act is snowballing. a man drinking his own semen out of his partners anus
The only way for a female to get pregnant is for a man to ejaculate semen into the woman's vagina. A girl can't get pregnant from a girl; a guy cannot get pregnant from a girl.
Only if they have a drop of a man's (or boy's) semen on their finger.
Viagra will have no effect on the semen and chances of getting pregnant
No. As long as there is semen ejaculated into the vagina, there are a possibility of pregancy.
No. Male urine does not carry semen the fluid that contains sperm. There is not possibility of pregnancy from urine.
If a man puts on underwear after recently ejaculating, then it is likely that such a stain will be left. If a man ejaculates while actually wearing underwear, this will also leave a stain.
Not with his own semen. Though if he came into contact with another man's semen (having sex with another man or even a woman who recently had sex), then the "foreign" semen could impregnate the woman.