Accidental penetration during foreplay: Does it break fast?

 Intercourse during fasting...

Validity of fasting: Intercourse while fasting ramadan fasts

If someone has intercourse during the day in Ramadan because he forgot or was unaware of the ruling, or made a mistake, it does not invalidate the fast, because of the report narrated by al-Bukhari (6669) and Muslim (1155) from Abu Hurayrah (may Allah be pleased with him), who said: The Prophet (blessings and peace of Allah be upon him) said: “Whoever forgets that he is fasting and eats or drinks, let him complete his fast, for it is Allah Who has fed him and given him to drink.”

An-Nawawi said in Sharh Muslim (8/35): This is evidence for the view of the majority, which is that if the fasting person eats or drinks or has intercourse because he forgot he was fasting, it does not break his fast. Among those who held this view were ash-Shafa‘i, Abu Hanifah, Dawud and others. End quote.

The one who is unaware of the ruling and the one who makes a mistake are like the one who forgets, because of the verse in which Allah, may He be exalted, says (interpretation of the meaning): {Our Lord, do not impose blame upon us if we have forgotten or erred} [al-Baqarah 2:286]. And Allah, may He be exalted, has said: “I have granted that.” Narrated by Muslim (126).

Complete Answer:https://islamqa.info/en/answers/406326/what-is-the-ruling-if-penetration-occurs-accidentally-during-foreplay-during-the-day-in-ramadan