For each rat, we designated the first three consecutive test sessions when they successfully engaged in sex (i.e. achieved ejaculation) as their “copulation days 1-3”. Across days, we found that bLRs showed a greater latency to mount the female compared to bHRs (A), and all animals generally showed a reduced latency to mount over the 3 copulation days (difference between days indicated by a versus b). All animals also showed fewer mounts per ejaculation across copulation days (B; indicated by a versus b). bLRs also exhibited increased latency to intromit (C) and fewer intromissions per ejaculation (D) compared to bHR males. All rats showed reduced latency to ejaculate across copulation days (F; indicated by a versus b versus c), although there were no bHR/bLR differences on this measure. Post-ejaculatory refractory period (time between an ejaculation the next mount or intromission) did not change over days, and did not differ between bHR/bLR groups (G). bLR>bHR indicates significant main effect of phenotype; * indicates p<0.05