Ay, ganyan din si baby ko noon, sobrang hirap talaga! The thing is, kadalasan natural lang yan and they usually grow out of it by age 4 or 5, pero may mga tricks na pwede mo subukan like redirecting their hands sa ibang activity, giving them a comfort object like a blanket instead, or (if okay na sila mag-understand) positive reinforcement pag nakita mong hindi sila nag-thumb suck, marami sa friends ko ang nagsimula rin dito at nakita nila talaga ang improvement. Kailangan lang ng patience kasi it's usually a soothing thing para sa kanila, hindi malicious, e.