Let her go cow girl first and get used to your size in a way where she has control and then when she has got used to you change position and take it slow, or is it you that only lasts a few seconds?
Ahahahaha ..lmao !!!! If i women can give birth to a 3.5 kg baby ...then not sure how big your dick is ?? Is it bigger than a watermelon??? you doing it wrong !!!!