Is Gusl necessary

Do you have to perform the gusl before the salah if you actually dont ejaculate but you feel a little wet or drop of some fliud comes out when some exciting thoughts go through the mind. Or is it that you can clean your private parts and changing the clothes will do. ( this is the case in which you dont mastubate , nor do u have intercourse, niether the wet dream and you actually dont ejaculate the semen...but just a drop oozes out of the *****). Very sorry if some mistake in language...