Green’s Dictionary of Slang

-tastic sfx

(orig. US) a qualitative intensifier, e.g. craptastic.

[US]Hope College ‘Dict. of New Terms’ [Internet] craptastic adj. Extremely disagreeable or unpleasant. [...] ‘I just found out about a huge exam tomorrow. Isn’t that just craptastic.’.
[UK]Roger’s Profanisaurus 3 in Viz 98 Oct. 13: fannytastic adj. Anything wonderful to do with female genitals. [Ibid.] 14: funbagtastic exclm. Upon seeing a glorious pair of breasts, one might utter ‘Funbagtastic!’.
[UK]Observer Escape 22 Aug. 2: It is an astonishingly romantic place, and consequently full of couples [...] the snog-tastic party continued around me.
[UK]Guardian Sport 13 May 12: ‘Poptastic, mate,’ he says when I hand over the bev.
[US]Ebonics Primer at [Internet] smacktastic Definition: either describing or implying the use of force of the backhand on a defiant prostitute or any other woman. Example: Ho, slow your roll less I get smacktastic on yo ass!
[UK]Observer 27 Feb. 29: Maybe they’d swing behind the shagtastic Tory.
[US]Eble Campus Sl. Apr. 3: fratastic [...] Those croakies (holders for sunglasses) are so fratastic.
[US]J. Stahl Bad Sex on Speed 115: JFK and Van [sic] Braun were doing the same drugs. Crank-Tastic!