So guys I need your oppinion on this one:

I am close to another 50 gems (ridiculous how fast you get these on DMM when compared to Nutaku, just wow), and I was contemplating if I should go and roll immediately or if I should onto them.
Not for a specific girl, rather than for a specific Gacha.
Is there a Ticket gacha where you get a 5* ticket on a 50 gems pull ? Or is that only Nutaku exclusive ? Coz Id much rather hold onto them and wait for such an occasion seeing how my last 3 pulls were utter shit and disappointment, to at least get one guaranteed 5*