Rig Veda
ज॒घने॒ चोद॑ एषां॒ वि स॒क्थानि॒ नरो॑ यमुः । पु॒त्र॒कृ॒थे न जन॑यः ॥ जघने चोद एषां वि सक्थानि नरो यमुः । पुत्रकृथे न जनयः ॥
The goad is (applied) to their flanks; the drivers force them to spread their thighs apart, like women in bringing forth children.
english translation