Sore throat from sucking dick

Does anyone know why you get a sore throat from sucking dick? I've heard that people get it but I'm wondering if anyone knows why.

It feels like I'm sick of have mild strep throat. I just deep throated for the first time yesterday and when I woke up in the morning, my throat killed!

Side note: when you suck dick, are you actually supposed to suck or is it just a phrase of speech? Like are you just supposed to go up and down and lick etc or are you literally supposed to create suction like sucking the juice off a popsicle or something.