Okay... Let's talk from some (more) things too...
How you wash your mouth? With soap? No...
So you need read some stuff how can you keep avoid some problem and make the risks low. (If you like BBBJ, CIM and licking)
Most of time if you got something fungal, bacterium, etc... the happen, because the reasion is: you wash "too rude" with regular body wash stuffs your dick. You can "kill" your foreskin-hole very easy... you kill your good bacteries and clean your defence too... good area for the attacker micro-dirty shits...
Your male smegma gland is your main defence of your dick. Keep it safe or you will suffer the problems...
You have two choice : Buy an intimate alkaline cleanser or use very few body wash under your "dick-skin" and keep away your dick-hole from the regular body-wash "soaps".
Yes, i know - i know, you can't do it dirty, but if you go spa, then use very few body-wash at your foreskin and remove with water fast. After the action, do same.
Another typical problem: If you use toothbrush before the sex, then it can damage your mucous inside your mouth. Buy Listerine, or something like that... or use toothpaste only with finger before the action...
And don't forget : very easy get some flu under the air-condition.
If you had very few girl before, then your dick can be feel irritation after the girl suck you, or if you use something "bad" condom. Canesten lotion is the best help.
Very extreme horror story, what can you surprise if you never heard before: A girl suffered an allergic attack after his boyfriend CIM, because the sperm...
By the way, if you go to a public toilet and the soap out of stock... you can get much more bad illness too... the life is dangerous... but you can hide at home and die as a virgin.