We need more context to answer. Lay it on can have some different meanings.
One is the one this Merriam-Webster definition gives https://www.merriam-webster.com/dictionary/lay%20it%20on which is to say in an exaggerated and insincere way. I would argue they got that definition wrong and that their definition is actually for the phrase “lay it on thick” the thick part being the exaggerated and insincere part.
Another is “lay it on me”. This is an informal phrase similar to “spill the beans”. Meaning tell me the whole story/truth even if it’s not easy.
The third is in the form “lay it on the line”. It has two meanings, both of which are given here: https://idioms.thefreedictionary.com/lay+it+on+the+line One is to risk something to gain something, the other is to speak bluntly. The risk meaning may have to do with placing money on the betting line or a metaphorical line as in the phrase draw a line in the sand, im not sure which.