O2 sensors - getting them back on??

[Frodo]

I was working on the driver side one (cylinder bank 2) when I posted my question. I finally pushed it on using brute force (or at least as much brute force as can be applied through 2 or 3 fingers!). The weird thing is that, on that side, it never "clicked" when it went into place. I'm pretty sure it's set: I pulled and pulled and it did not come back out.

The other side was easy: I pushed with moderate force and it emitted an audible "click".

Thanks Steve.