The back of the throat is more open to infections like gonorrhea. Lick the shaft of his dick and his balls, while avoiding sticking the head of his dick in your mouth. Be aware of the condition of your mouth and throat. If you notice sores in your mouth, if you have a cold sore, or a sore throat, you might want to be more cautious and take additional steps to protect yourself. If you have had recent dental work, have recently bit your lip or the inside of your mouth, or have gum disease or inflammation of the gums, you can take extra precautions to protect yourself, such as using a condom when you suck.
Some guys enjoy group sex, or sucking several guys in an evening.
Each time you suck someone, especially if you are taking their dick far down your throat, you can irritate the lining of the mouth and throat. Repeated sucking over several hours can mean your mouth or throat may be more open to infection. If you are sucking for several hours, you might want to be more cautious as your sex session progresses. Try to make it a habit to take a piss right after someone sucks you off. This can flush bacteria out of your dick and help you to avoid sexually transmitted infections.