Hinduism & Indian culture before western influence did not view sexual activity as a taboo or unclean act.
In many parts of India, there are photos from older eras that show women being topless and temple sculptures etc. The fact that these are on temples would indicate advanced civilisation and architecture.
Sources (mouseover to view hidden images)
There are also ancient manuscripts such as Kama Sutra ("Manuscript of Love") that go into detail regarding love and sexual relations.
As such, before the Portuguese (Catholic), Muslims & British (Protestant) introduced their puritan and prudish views, India was quite liberated, and did not view sex as a vile act needing "cleansing".
This does not mean Indians were unhygienic or not clean. To the contrary, travelers to India, such as Marco Polo, have observed and recorded that Indians bathed multiple times a day and were quite fastidious about being clean.
The people here go into battle with lance and shield and they go stark naked.[...]
Another one of their customs is that all of them, male and female, wash their whole body in cold water twice a day - this is, morning and evening. One who did not wash twice a day would be thought an ascetic, as we think of the Patarins.
The Travels, Marco Polo, c. 1300 AD
So I'd presume that once business is done, couple would proceed to wash all that sweat off ;)