If one thinks this is stupid question (and that’s not me, to clear the things out), then I’ll provide even more stupid answer.
I understand it as “to the eternity” what in the context of sentence could be highly possible he’d say to a bit amuse audience …
Well, just my “naughty” suggestion as I’m in much better mood (thanks to @aran) then I was a day ago. 
Thanks, so you think it was “Tan byth”? 
Yes, why not. Since it was night and people think a lot about this theme. I’d have to hear what mood he was in though. But yes, I think it was “tan byth”
Tan bump? Till 5 (O’Clock)?
Tan beth? Till a bit? (I don’t think I’ve heard peth used like this before, but Tommo appears to be a law unto himself in his usage and abusage of the language - and is all the more fun for it!)
Not really sure of the mood, but as he is always trying to be funny I guess that it was humour which fits in!
Oooh, it could be that too! Thanks. Notwithstanding, is tan byth something that would be said?
Tommo appears to be a law unto himself in his usage and abusage of the language
Yes, he confuses me quite a bit, but I do enjoy the programme even if it is a bit loud!
I’m guessing it was this, since his show normally finishes at 5pm Mondays to Thursdays…
When programmes like Y Gwyllt are made in both languages, I suspect they use the dialogue in one as subtitles in the other. This makes colloquialisms more ‘real’. I’m sure they do it for children’s programmes. My little dog and I watch a lot of S4C for children and, if we lose a bit of the programme, may watch the end of the English version. Names are different as well as dialogue, Beware of subtitles!!! 
p.s. edit - I seem to have lost the last bit of the quote above!! I think it said ‘spoken Welsh’!!! Mae ddrwg gen i, carole_1!!! 
True - you have to keep on your toes, which is one reason I don’t think subtitles are (necessarily) just an easy cop-out. Spotting the differences means you have to keep awake and alert.
Ah, I assumed you were getting down with the kids and this was some new street talk I hadn’t caught up with! “Hey it don’t match the spoke, it’s goldarned broke…”
Oh, no! And so love "Tan byth thingy … - hehe
I really did laugh out loud!!! 
I have a lot of fun when things are printed in both English and Welsh (example in a minute) translating the Welsh to see what they have used to say what the English says. In this way it can actually be somewhat instructive of normal Welsh language use.
Example is the wedding invitation we got last week from my nephew and his Welsh fiancee. The invitation itself is all in English (though I suppose they might have had a Welsh-language version printed for the reception in Wales…) but they have a URL for a wedding website that is bilingual. The most instructive one here was this paragraph in English:
Which was given in Welsh as:
I am left wondering who wrote which first, or if they worked on it simultaneously. The Welsh certainly gives the same meaning as the English, though not in precisely the same way. Love it!
I can see that they differ slightly, but still give the same overall meaning. That use of “so” is a relatively modern (I think) English idiom, and I’d have no idea at all how to render it in Welsh.
Maybe there’s a way to work “mor” into that somewhere? Or even “ni wir yn edrych ymlaen” is a similar meaning, I think.
or “gymaint” - so much?
oops - “mor”! - I should have remembered that. Thanks.
mor sounds wrong to me in that context. wir sounds good, though.
I think edrych ymlaen yn fawr would work, too.
I also note that they are edrych ymlaen i the thing. Technically, edrych ymlaen at is more correct, but I would suggest that i is more popular currently, and if you’re of the opinion that grammar is a matter of democracy, then edrych ymlaen i is fine. Despite it really grating on my ears*.
*Don’t worry, I’ll get over it. 
Dewi Prysor tweeted - Da ydoedd! Diolch yn fawr Sesiwn Fawr am y gwadd! Gwych
Anyone an idea on - Da ydoedd?
Google translate says this:
It’s a formal form, equates to ‘oedd’
edit: fyi, it is mentioned in “Ymarfer Ysgrifennu Cymraeg” section 22 - Rhai berfau afreolaidd pwysig, p 101