I use Doom Shaman to special summon Dark Necrofear from the grave and use Self Mummification + Grave Squirmer to loop. Got 8-10 summons per duel, but after ≈20 duels I still didn't unlock the mat. So you definitely have to summon it the traditional way. So instead, use Duke Shade to sacrifice DarkNecro and use Dukes effect to bring her back to your hand and then special summon properly. You can get at least 5 per duel. Keep Doom Shaman tho, he looks cool.
can someone confirm if dark necrafear and lava golem must be summon properly to count? because they need to be special summon that way just the first time, later you can summon from the graveyard for instance, but don't know if that counts for the playmat