I think you're talking about the air intake. I don't think mine is a 2.5, has 2 small holes above the threading, but that's usually why there's holes at the base. I haven't had any "gurgles" on my vivi yet, it's the quietest add. that I've used so far. Try not to fill right up to the top marker, the next little line down is dandy.
If you blow through (when there's liquid in tank) you'll just keep pushing more liquid through, at least that was my experience with cartotanks and clearos. After using clearos/cartos/drip I've come to realize a small amount of liquid on the battery connection isn't going to kill it. You can try to do a "primer" or few (quick hard pulls without firing the battery) to draw excess liquid up to the coil. Vape like normal. You may need to do this a couple times to get all of it up.
Really, don't worry too much about a bit of liquid on the battery end. I'm fairly certain (Though haven't tested myself) that PG and VG aren't very electrically conductive and I don't understand the datasheets I've found on them.
Anyways, anecdotal evidence time! When I first started dripping (without really reading about it here...derp) I put ~5 drops on the atty, flooded of course, but as a noob I tried vaping it anyway. Had at least one full drop of liquid on it (and my hand, and the battery casing) and the battery is still working dandy to this day.
Now, if you are using an automatic/unsealed battery you have to be more vigilant about not overfilling/flooding, but even then a small amount of liquid isn't the end of the world. It's mainly a problem with it getting IN the PV, not a little on the connector.
