is it possible to do an horizontal piercing in  the first third of the
tongue (2 to 3 cm backwords from the top of the tongue )

Hello Polderis,

Correct Positioning is critical with tongue piercings.

Horizontal Piercings are very likely to cause nerve damage and are
never recommended.

"The correct place is in the midline, on the front third of the tongue
far enough back so that the jewelry does not hit the teeth when
speaking but not so far back that the piercing is stretched when
swallowing or yawning. The further back the piercing the worse the
swelling and pain during the first week."
http://www.thebananabar.com/webpages/bodypiercing.htm


Placement

"It has be done both at the tip and deeper into the tongue, and
multiple simultaneous placements have been shown to be possible. The
placement that puts that impedes speech and eating less for the
individual getting pierced should be used. The part of the tongue that
bends with speech etc is NOT a suitable placement for this piercing."

"The area decided upon to be pierced should then be checked for blood
vessels with a flashlight. It is important to remember that not
everyone's anatomy is suited for this piercing."

"Most piercers do not consider this a viable piercing because of the
almost unavoidable side-effects.
http://wiki.bmezine.com/index.php/Horizontal_Tongue_Piercing


Search terms:
horizontal piercing  tongue


I hope this helps!


Best regards, 
Bobbie7