>>20872139VIX is more often than not "low", front VIX futures are close to spot VIX while farther VIX futures tend to be more average due to the priced-in possibility that VIX will spike at some point before these contracts expire. So typically what that means is that when a VIX future contract expires (at the same price as spot VIX) then next contract that will expire a month later is priced $0 to $3 higher, so if you long such contracts that represents how much you lose a month and if you short them that represents how much you gain.
The risk of this strat is that if shit really hits the fan front month futures might get high ($33 in Feb 2018 for Volmaggedon or $80 in March 2020) so you need to scale your short position to not get liquidated by a huge spike. If you scale it properly you get consistent gains, more consistent than with equities. Starting 10 years ago you would have accumulated about $110 in contango gains per $12 to $20 contract, although due to the safety required you would have needed to be able to take a temporary loss of $70 per contract to survive all the drama. And basically your gains come from people using VIX derivatives as an hedge, so basically they're paying you to soften the blow if things go suddenly bad, so unlike them you have to be positioned to be able to take the blow and wait things out without closing positions.