Charak Samhita
क्लैब्यं सम्पद्यते तस्य शृणु सामान्यलक्षणम् । सङ्कल्पप्रवणो नित्यं प्रियां वश्यामपि स्त्रियम् ॥१५५॥
A person desiring sex is unable to complete sexual intercourse with loved and even obedient female due to loss of erection.
english translation
klaibyaM sampadyate tasya zRNu sAmAnyalakSaNam । saGkalpapravaNo nityaM priyAM vazyAmapi striyam ॥155॥
hk transliteration by Sanscript