MacBooks (and many laptops) have a tiny amount of alternating current that leaks through the metal chassis to ground. When you use the compact 2-prong power adapter (the “duck head” without a ground pin), there’s no path for this leakage current to safely flow to earth ground — so it flows through you instead, creating that tingling sensation.
Interestingly I haven’t felt this when using my 2 prong NAND Anker adapter.