Lube injection

My partner and I are thinking about trying pegging. I have some experience with prostate toys and butt plugs. Normally when I use those I feel like most of the lube gets scraped off when I insert them. Which for those normally feels fine since they are not moving. With the thrusting of pegging I would want to make sure there is plenty of lube inside. Does anyone inject lube first? And if so how much?