extrude in mirror being weird

Hey peeps,

Noob here, I’m following along a tutorial to model a puppy (https://www.youtube.com/watch?v=bMKBfqUytvo&spfreload=1)
and I can’t extrude anything from the mouth of mine (like the tongue). When I do it goes all caddy wompas on me. Sorry, the only way I know how to describe it. It works for him starting at about 6 minutes 4 seconds. I’ve also noticed that I can take the vertices inside the mouth and move them where ever I want. It’s like they are disregarding the mirror. Help please!

Notice that you have some vertices crossing the centre line of the mirrored object.
Move these to the centre or increase the mirror modifier merge limit so the vertices are correctly merged together

Your central seam somehow is not actually central (if you select all the seam edges you can see in the Transform panel that the average X position is below 0). This means that mirror modifier’s Clipping setting won’t work, since some vertices are already past the threshold.
Select all center edges and scale to 0 along X axis, and you should be good to go.

Oh, Richard already caught it.

thanks for the timely response. But I tried that as per the video I was watching to set the centerline vertices to 0 on the x axis. And I just tried to raise the merge limit and that didn’t work…

well, I MANUALLY set the inside vertices by dragging them instead of hitting s x 0, and it worked. One of those quirky little things I guess. Thoughts?