Depending on your laptop, if you haven't cleaned your CPU fan you should be able to access the CPU fan from the bottom of your laptop, it should be just a simple panel next to your battery and ostensibly is the one covering the CPU/RAM access. You should use compressed air to clean off the dust from your CPU fan and the grate that's covering it, then also if the issue persists then also invest in an external laptop fan or at least use your laptop on a stand off so that air can circulate underneath it while gaming.