I think with this characteristic there's a need to parse out some of the non-cannabis variables.
The first would be, time of life / years spent smoking. When I was a teenager, everything was giggly weed. It didn't really matter if it was 2 year old smalls, or fresh indoor, or OG or blue dream. It was all hilarious.
The second would be, set and setting. Weed hits me as giggly when I'm flowing a lot of dopamine or otherwise good hormone juices in the first place. Examples would be, an old friend has come to visit, or I'm hitting on someone and it's going well, or I'm at a show I'm stoked on.
That being said, for me the strains that really put me in the mood to laugh and joke, are those sativas that lack the racy edge.
Amongst the many that can accomplish this, there's one pool of landrace that I think epitomises the type of high. I'm thinking of African tropical sativa, Ethiopian and Jamaican stuff. Not Durban, that's racy for me.
I had somebody gift me some of their headstash Ethiopian "red tree" flower, that hit this spot... old lambs bread, but I don't know where to get it (lmk anybody)... Probably any Ethiopian landrace is gonna be a good shot at this profile. Real seed co. Idk. Good luck.