Is It Necessary to Do Ghusl If You Do Not Find Semen after Wet Dreams?
Question

When I wake up from sleep straight after having a wet dream, I am certain that nothing came out of me, whether Maniy (semen) or Madhiy (presemen fluid), but because of a great deal of Waswas [whispers from the devil; persistent intrusive thoughts], I examine the urethral sphincter, as if I can find something small inside it, and I squeeze the penis but nothing comes out, and I think it most likely that this is not Maniy. 
I experience this confusion regarding dreams only, as a result of your Fatwa which says that everything that comes after a wet dream is usually Maniy. 
This is something that makes a person confused. Please advise me, may Allah reward you.
Praise be to Allah.If someone thinks that he had a wet dream , then he wakes up and does not find any wetness , he does not have to do Ghusl.
Al-Bukhari (130) and Muslim (313) narrated from Umm Salamah (may Allah be pleased with her), who said: Umm Sulaym came to the Messenger of Allah (blessings and peace of Allah be upon him) and said: O Messenger of Allah, Allah is not too shy to tell the truth. Does a woman have to do Ghusl if she has an erotic dream? The Messenger of Allah (blessings and peace of Allah be upon him) said: “Yes, if she sees water (discharge of fluid).”
Ibn Qudamah (may Allah have mercy on him) said in Al-Mughni (1/130): 
“If he thinks that he had a wet dream , but he did not find any Maniy, then he does not have to do Ghusl . Ibn Al-Mundhir (may Allah have mercy on him) said: All the scholars from whom I acquired knowledge unanimously agreed on this… If he wakes up and sees Maniy, but does not remember having a wet dream, then he must do Ghusl . We do not know of any difference of opinion concerning that either. Something similar to that was narrated from `Umar and `Uthman, and Ibn `Abbas (may Allah be pleased with them), and was also stated by `Ata’, Sa`id ibn Jubayr, Ash-Sha`bi, An-Nakha`i, Al-Hasan, Mujahid, Qatadah, Malik, Ash-Shafa`i, and Ishaq (may Allah have mercy on them), because what appears to be the case is that it was emitted during a wet dream, and he forgot.”
If you do not find any Maniy on your body or clothes, then you do not have to inspect the urethral sphincter; rather this is something that will provoke and strengthen Waswasah [persistent intrusive thoughts].
Allah, may He be Glorified and Exalted, has not enjoined you to undertake this examination, whether after sleeping, or following urination. The teachings of Islam do not impose such difficulty on people. Allah, may He be Exalted, says (interpretation of the meaning):
“and [Allah] has not placed upon you in the religion any difficulty.” [Al-Hajj 22:78]
This cannot be understood from our fatwa.
Our advice is to stop doing that, and not pay any attention to the Waswasah ; you should remember Allah a great deal and obey Him, because this is the best remedy for Waswasah. May Allah grant us and you well-being.
And Allah knows best.