The absalute best method for taming these creatures it to drop them in a small box, (you can use a ptera for that). Once it's in the box all you have to do is get a heap of mejoberries, then to tame simply trap it in the corner of the box. The reason for this is that it's always in "bug mode" (the mode were it gets scared or something and it's taming percentage drops). But this way it's taming percentage does not drop at all for some reason. I have tamed multiple max level pego's with this method. Do not listen to what people say about having it in a large space. Go for small and trap it in the corner, as simple as that.
'You have been robbed! 5 fiber'
Ah, look at it run with the little bag
'You have been robbed! 3 wood'
I dont need that anyway
'You have been robbed! 100 narcotics'
O HELL NO
'You have killed! Pegomastax lvl 10'