where i can find this Full video ?

It's not a video but set of pictures featuring Lightning and Serah.
There are some I could find:
http://rule34.paheal.net/post/view/504319#search=Lightning
http://rule34.paheal.net/post/view/461041#search=Lightning
http://rule34.paheal.net/post/view/751477#search=Lightning
http://rule34.paheal.net/post/view/751476#search=Lightning
http://rule34.paheal.net/post/view/751475#search=Lightning
http://rule34.paheal.net/post/view/751474#search=Lightning
http://rule34.paheal.net/post/view/751473#search=Lightning
http://rule34.paheal.net/post/view/751472#search=Lightning
http://rule34.paheal.net/post/view/519474#search=Lightning
http://rule34.paheal.net/post/view/944503#search=Lightning
http://rule34.paheal.net/post/view/894436#search=Lightning
http://rule34.paheal.net/post/view/894009#search=Lightning
http://rule34.paheal.net/post/view/892274#search=Lightning
http://rule34.paheal.net/post/view/889486#search=Lightning
http://rule34.paheal.net/post/view/955814#search=Lightning
http://rule34.paheal.net/post/view/953767#search=Lightning
http://rule34.paheal.net/post/view/953047#search=Lightning
http://rule34.paheal.net/post/view/953032#search=Lightning
http://rule34.paheal.net/post/view/953023#search=Lightning
http://rule34.paheal.net/post/view/953024#search=Lightning
http://rule34.paheal.net/post/view/953027#search=Lightning
http://rule34.paheal.net/post/view/953028#search=Lightning
http://rule34.paheal.net/post/view/953029#search=Lightning
http://rule34.paheal.net/post/view/953030#search=Lightning
http://rule34.paheal.net/post/view/953013#search=Lightning
http://rule34.paheal.net/post/view/951288#search=Lightning
http://rule34.paheal.net/post/view/998392#search=Lightning
http://rule34.paheal.net/post/view/998391#search=Lightning

You can find more here:
http://rule34.paheal.net/post/list/Lightning/1
and
http://rule34.paheal.net/post/list/Serah_Farron/1

It's not a video but set of pictures featuring Lightning and Serah.
There are some I could find:
http://rule34.paheal.net/post/view/504319#search=Lightning
http://rule34.paheal.net/post/view/461041#search=Lightning
http://rule34.paheal.net/post/view/751477#search=Lightning
http://rule34.paheal.net/post/view/751476#search=Lightning
http://rule34.paheal.net/post/view/751475#search=Lightning
http://rule34.paheal.net/post/view/751474#search=Lightning
http://rule34.paheal.net/post/view/751473#search=Lightning
http://rule34.paheal.net/post/view/751472#search=Lightning
http://rule34.paheal.net/post/view/519474#search=Lightning
http://rule34.paheal.net/post/view/944503#search=Lightning
http://rule34.paheal.net/post/view/894436#search=Lightning
http://rule34.paheal.net/post/view/894009#search=Lightning
http://rule34.paheal.net/post/view/892274#search=Lightning
http://rule34.paheal.net/post/view/889486#search=Lightning
http://rule34.paheal.net/post/view/955814#search=Lightning
http://rule34.paheal.net/post/view/953767#search=Lightning
http://rule34.paheal.net/post/view/953047#search=Lightning
http://rule34.paheal.net/post/view/953032#search=Lightning
http://rule34.paheal.net/post/view/953023#search=Lightning
http://rule34.paheal.net/post/view/953024#search=Lightning
http://rule34.paheal.net/post/view/953027#search=Lightning
http://rule34.paheal.net/post/view/953028#search=Lightning
http://rule34.paheal.net/post/view/953029#search=Lightning
http://rule34.paheal.net/post/view/953030#search=Lightning
http://rule34.paheal.net/post/view/953013#search=Lightning
http://rule34.paheal.net/post/view/951288#search=Lightning
http://rule34.paheal.net/post/view/998392#search=Lightning
http://rule34.paheal.net/post/view/998391#search=Lightning

You can find more here:
http://rule34.paheal.net/post/list/Lightning/1
and
http://rule34.paheal.net/post/list/Serah_Farron/1