I also would love to be able to just hold and cuddle my piggies, and I know my son (turned 5 yesterday) would desperately love to as well (think he's a bit disappointed he hasn't been able to so far). But we are still very far from that. And to be honest, it's looking like only one of them will be a lap pig as the other hates it.
Patches is the dominant piggy and is so super confident in the cage. When I bring food she stands up on her hind legs to get to it first, and will even put her front paws on my hand and sniffs me and nibbles me and doesn't seem scared of me at all. But if I try to stroke her she runs. When it comes to catching them (hearding them into a snuggle sack for lap time) she chatters her teeth a lot and gets scared. Once out the cage and on my lap (in the empty bath) she is terrified. She burrows so deeply and crazily into the snuggle sack that most of the time I can't get her out to cuddle at all. And she chatters a lot. I mean I could get rough and force her out, but that's cruel and I don't want to traumatise her. So I try a few times then rather resort to stroking her in the cuddle sack. Even getting her out to weigh her is a major mission and she stands on the scales looking totally terrified. When I got them out for nail clippings the other day she was the one that nipped me towards the end because she just couldn't stand being in my arms any longer.
Nia, on the other hand, is the under pig and more nervous of me in the cage. She's the first one to run away if my hand goes in, though she's definitely gotten more confident about taking food from me. But when I spot clean etc she runs and hides. She, however, is usually the first one to agree to go in the snuggle sack for lap time and she will sit happily on my arm for quite a while whilst I stroke her. No chattering. She does get somewhat of a wide eyed look about her initially, but that soon settles with stroking and talking. She's the one I suspect will become the piggy happy to do lap time and cuddles. But I definitely think we still have a few months before we reach that point.
I'm not sure there is really anything one can do to make it happen faster to be honest. I think some just like being held, and others don't.