A man ejaculates into his partner's nose while the partner is inhaling the semen, almost like when you have a runny nose and you are hocking up a loogie but instead of spitting it out the partner swallows the sperm when they feel it slowly running down the back of their throat.
Similar to crowd surfing except it is done in an inflatable raft and normally with the DJ in it. As the name implies, it is usually done at raves but also clubs (discos) and concerts.
EDM DJ's love raver rafting. Steve Aokijumped off a balcony into a boat and raver rafted back onto stage.