Gonzalez

After trial by jury, appellant Danny Lopez Gonzalez was found guilty of one count of forcible rape (Pen. Code, § 261, subd. (2)) and one count of forcible sodomy (Pen. Code, § 286). He was sentenced to state prison for the midterm of six years on both counts, the sentences to run concurrently. He received 113 days’ custody credit and 38 days’ conduct credit for a total of 151 days.

On appeal, appellant contends that (1) there was insufficient evidence of penetration to support his conviction of forcible sodomy; (2) the trial court committed prejudicial error by failing to give certain jury instructions sua sponte; and (3) his presentence custody credits were improperly calculated.

Facts

On June 13, 1979, Mrs. Dolores E., an elderly widow who had recently arrived from Mexico, was living at the house of her friend Maria G. At about 11 *789 a.m., appellant came to the house. Mrs. E. allowed appellant to come inside because she recognized him as a friend of Maria’s to whom she had been introduced two days before.

Mrs. E. explained that Maria and her family were not at home. Appellant asked for a glass of water and followed her into the kitchen. Mrs. E. then went to her…