A dickhead who constanly spurts stupid shit out of there mouth which they have consumed from other people.
Person 1: "Did you know that people who have a larger index finger than ring finger have a 12 inch monster penis"
Person 2: "Shut the fuck up you Cum-Guzzler, You believe everything you hear.
Cum-guzzler could be used in roughly the same way as "dickrider". Basically, someone who likes something to the extent that they'd constantly bring them up and annoy the fuck out of others. It could be also used to describe someone that likes someone when the feeling isn't mutual.
1. Sophie is so fine oml
2. Stop being a cum-guzzler, Finn. She doesn't even know you