Once you see one of the players ingame (team is totally not counting at all) after the loading screen, and one had a Hextech-loot skin, do this in order to bully them.
/all Bloody Veins : Nice skin
/all Mr.Y9l9 Sw$g : Thx
/all Bloody Veins : Veigar :) _(X = Champion with a not Hextch loot skin, for example the X in here is Veigar)_
/all Bloody Veins : Not you Darius/Vayne/Annie, i meant Veigar
this has the highest percantage of working, and it makes the owner of the Hextech-loot skin feel awkward most of the time :^)