Before joining UKP, I tipped a WG who had given a good service and on the second visit, asked for a tip. When she kept asking for tips, I looked elsewhere and started finding girls who were way better vfm at half the price.
Never pay tips. They're hookers, not restaurant waitresses. Even if Sergei or the maid takes half their earnings, they still get 50+ p/h. I've never given a gift to a WG and never will - fluffies who fall in love do this. If price+extras is more than 150 p/h or 80 for half hour and the girl isn't anything to write home about, I won't be returning.