Usual concerns about having small penis are related to having intercourse and penetrating. In that case, the following sex positions may be done when under the sheets: 1.  Missionary position – place under a woman’s bottom a large pillow. 2.  Doggy style – with woman’s legs together. 3.  With legs together, the woman should be lying face down and the man from being penetrating in her with his knees outside her legs. Or test with anal sex since the anus is smaller or tighter than the vagina. However, this is not usually recommended as it posts risks and may be a painful experience for the woman.