I am also trying to conceive and honestly, I feel too scared to try anything like that. A regular pregnancy kit or checking with a doctor seems much safer and easier.
This is a total myth and highly unhygienic. Please do not insert fingers to check, just go to a chemist, buy a standard test kit, or get a blood test done.
Please don't try checking this way, as it can cause infection and is not reliable at all. The safest and most gentle way is to use a simple home urine test kit.
Urine test kits are actually very cheap, you can get one for 50 rupees at any chemist. Please don't try using fingers as it's risky and won't give a real result anyway.