The command p pastes below the cursor and P pastes above the cursor. What's the command to paste in the line where cursor is?
This all depends on the type of data in the register you're pasting. If the data is line-oriented data (yanked with yy for instance) it will be pasted as a whole line above or below the cursor. If the data is character-oriented (yanked with e.g. y2w) then it will be pasted at or before the cursor position in the current line.
See :help linewise-register
for more info on the interaction between the type of register and the put command.