If you're getting clitoral sensation, I'd advise stimulating it if you're in the mood, not to be too graphic, but often before I dilate, I get in the mood and masturbate until climax. At that point, the vagina becomes lubricated and the dilator is easier to insert. As others have mentioned, as vibrator can help too. Also, it pays to ensure that the dilator is inserted right in and pushes against the wall to stretch it, which may seem obvious, but it can be easy to let it slip out a bit when holding it for a long period of time.