Me& my boyfriend likes to have sex with choclate syrup and stuff like that. If he puts that in my vagina could that cause a yeast infection?

Probably.

YES its articifical sugar. If your not cleaning properly then it will result in a yeast infection.

Yep, sugar is a yeast bomb waiting to happen. Just say no to food in the bedroom! If he wants to experiment with edible products have him go with a flavored lubricant designed for oral sex. They make them in every flavor you can imagine.