Which poses do you find hardest to engage the bandhas?

Source: Yoga Journal

I had no idea my uddiyana bandha was totally not engaged until the teacher came and put his hand on my belly in revolved triangle pose and revolved side angle pose. I normally pay pretty good attention during my sun salutations and non-twists to suck in the belly, but in these poses the twists make it feel like the belly must be sucked in already, since it's squished against the leg (sort of) right? Wrong. I felt like my gut was pushing directly into the teacher's hand and absolutely nothing happened when I tried to order my abdominal muscles to draw the belly back in. Can you imagine how pathetic I felt at that moment? I don't think the belly actually looks that big in twists, but it sure felt like I was 5 months pregnant at that instant. For the rest of the class I was totally self-conscious about my belly in all the twists, and I discovered that I could engage the bandha a little bit in Mari C and D. I don't know if it was because the twists in these poses are kind of lop-sided, providing slightly more space for the ab muscles to maneuver, or did some neural pathway from the brain become established to the abs sometime between the standing series and the seated poses.

So, cybershala, which poses do you feel the easiest to engage the bandhas and which poses are the hardest? For me the easiest pose to feel my bandhas is the 2nd last pose (not counting savasana) -- padmasana. I have heard that bandha engagement should be easy in urdhva padmasana because the organs get out of the way when upside down, but I find it the other way around.. they get in the way of my bandhas (interfering with the diaphram??)  Or maybe I'm just not used to being up side down still.

Don't even ask me about mula bandha. When I worry about it I squeeze everything down there, including unnecessary butt muscles, leg muscles, hip flexor stuff, and a whole bunch of other stuff that I don't know controls what but pretty sure have nothing to do with the perineum.