To put me over the edge, I typically think of one of my partners doing something they enjoy (like anal, or being tied up, or double-penetrated).
Then I use an electric toothbrush (that is not ever in my mouth) on my clit while watching porn.
Sometimes lesbian, sometimes college party scene, sometimes public bondage stuff.
I put my laptop next to me and use my vibrator under the covers so my roommates don't hear.
I start low and increase the strength as I get more turned on.
I try to wait until a good part before letting myself finish.