it depends on the type of Viagra, there is no specific Viagra pill there are Viagra to raise the blood pressure to make the penis hard and there are others to make you last long basically prolong the number of time in a sexual relationship as a result of giving you more resistance and of course it have a lot of side effect like Headache, flushing etcetera...... But i Always thaught if Alan had took the risk Clara would be more satisfied but anyways i can not apply this logic in a NTR game that would make nonsence
In the both case Clara was forced to insult his intimacy but in the path when she cheated only with Leon she's feeling more guilty about it so this insult we could say it's not entirely true, Alan is probabely the average in the company but that doesn't mean he has a little one