Tips-Training partner constantly spamming underhook wrestle ups from side and half guard

Hi all,

I roll with a training partner on a regular basis who is getting pretty good at getting underhooks from half and side control.His guard is easy to pass but he is quite good at looking to bump me forward to come up on a single leg. I stuff this pretty easy but keeping him pinned can be hard , so I don't get much into a position for subbing.

I know the following works- but it doesn't seem to keep him pinned these days.

• C Grip armpit and reverse crossface to keep them pinned and stop them coming up- ala gordon ryan
• Keep my own elbow tucked to avoid an underhook being given.
• Walking to North South
• Looking at darces and 3/4 breakdowns

But its actually annoying rolling with him, I was in kesa the other day on top and he constantly knee bumps to get me Forward to get on a single, I had decent control as-well.

The hardest part is that he is extremely vigilant with his own elbow positioning, to avoid me getting an underhook on him, so while I can pass guard and even mount , he rarely gives up an easy underhook.

Any tips?