Taking a Massive Dong

We're talking like 8" of full-on girth and I just... good grief, I can barely handle it. Anything more than half of that thing in me is just instant regret, or maybe he's just hitting my G- spot? It feels like a lot of pressure in one area and its almost sharp. It doesnt seem like that feeling goes away, either, no matter how long we're banging for. It's honestly more painful than it is pleasant. I want to know how to deal with this better, since it seems like this guy is gonna be around a little bit longer than most (maybe not.)