This was going off the rails at “He wanted to be tied to a chair and have a shake funneled down his throat. I did it, albeit a bit uncomfortable myself since it's not my sauce.”

I don’t know you or your situation or what this guy is like. But I feel like these are really weird requests for your first time with someone. Maybe I’m just old fashioned but I feel like you need to work up to something like… forcing a milk shake down someone’s throat!!?… over a period of time, if at all. You shouldn’t have to degrade yourself or do something that makes you super uncomfortable, especially the first time with a guy! I have no idea where this guy gets these strange desires from (porn?), but to me that was the bigger red flag than his sexual inexperience. If he’s into you then you can show him what works for you, but I feel like this whole encounter was stained more with the weird stuff than anything else. Maybe he thinks this is normal from whatever he has been watching and just needs you to tell him to calm down a bit.