[NSFW] What does it feel like for guys to climax?

So I apologize if this questions is offensive or whatever, but I’ve been trying to get this question answered from my bf – who gave me a pretty vague idea. So let me hear your thoughts – what does it feel like, as a guy, to climax? Is it different when you’re doing it solo (which we all know you do), when being jacked off, in someone’s mouth etc.
*apologies if this totally throws people off (just generally curious ;))