Well citrus, just means the dragon has yellow coloring.
Really isn't a difference between a yellow tiger, and a citrus tiger.
It's like using the word magma to describe the color red. It's to make it sound cooler..
Tiger, is just a type of pattern on a dragons back, which doesn't look hardly any different, IMO, from a normal dragons patterning.
So, if they say it's a citrus, first step would be to make sure it has yellow coloring.. If thats true, than part one is complete.
If they say it's tiger, look for a slightly different marking pattern on their backs. If it looks like it's different, or it looks like something you like, than there is your citrus tiger for you.
But ultimately, as far as morphs go, that would be considered a normal dragon. Albeit a yellow normal dragon with "tiger-like" markings on it's back.
-Brandon