So far there are only 6 cards in the game that can attach additional Xyz Materials to this card in order to activate its second effect: "Overlay Eater", "Xyz Unit", "Overlay Capture", "Hazy Pillar", "Spirit Converter" and "Overlay Regen". The latter two are the most recommended, as "Spirit Converter" can attach more that one monster as an Xyz Material, combined with easy swarm capabilities, while "Overlay Regen" is very easy to use, as it becomes material itself, making it a quick means of gathering the materials needed.
Have at least 2 copies of "Overlay Regen" ready as soon as you Xyz Summon this card. Its effect second effect should be activated right away or it may not be possible at all.
It may be possible to activate the second effect of this card if you have 2 copies of "Number 19: Freezadon" on the field. As you activate this card's effect, activate the effects of the copies of "Freezerdon".
"Hysteric Party" with a handful of "Harpie" monsters in the Graveyard can quickly Summon this card as well as any other Rank 4 Xyz monster.
If you Xyz Summon this monster using three "Harpie" monsters and use its effect, you can activate "Hysteric Party" and Special Summon the monsters used as the Xyz Materials and make another Rank 4 monster, like "Harpie's Pet Phantasmal Dragon" and "Evilswarm Ouroboros".