Reference for Shabbat 280:6

ואמר רב חסדא בר בי רב דזבין קניא ליזבין אריכא טונא כי טונא ואורכא ממילא

R. Kattina said: He who stands in the middle of a [marital] bed is as though he stood on a woman's stomach.<span class="x" onmousemove="('comment',' Because he is incited to impure thoughts. ');">⁵</span>

Jastrow

Jastrow