Ah yes sorry I did mean Masculine. But yeh for me planning and going has slightly different meanings.

If I said in English "I am going to go swimming" it hints that it is going to happen soon, almost immediate unless stated otherwize (I'm going to go swimming on sunday). And I'm planning to go swimming would mean you are making a plan, and this hints that it first needs to be planned before you end up heading in this direction. I don't think thats just me. For example I might say; I'm planning on visiting France (one day in my life I want to see France)/ I'm going to visit France (it is a definite thing I've planned)... I dunno I'm not that good at my own language as it is :P just how I see it.

And yes I guess I understand it's just hard when trying to learn the rules so that it will crossover to other examples. But I guess svoih could be genitive and druzyej could be dative and it makes just as much sense as both dative!